Intellectual Disabilities

Please note: Terminology

In 2011 the terminology for Intellectual Disability was officially changed from the formerly acceptable terminology "Mental Retardation" (MR). We have made our best efforts throughout our vast library of information to make this change for those areas where we can change the terminology to the presently accepted terminology of Intellectual Disability, however for book titles we are powerless to make this change. Given the immense number of pages and information we provide, we ask you help us by copying the web address in an email to us if you happen to find a reference to Mental Retardation.

Some of these files may require Adobe Reader for PDF files. These files are noted as PDF at the end of the site explanation. If you do not have Adobe Reader you can download it for free


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Adults with Intellectual Disability

  • Aging with ID : Older adults with developmental disabilities are living longer than ever before. Most have the ability to live happy, productive lives in their communities. Like other older adults, it is critical for adults with developmental disabilities to receive regular vision screening to identify age-related changes and eye diseases that can have an impact on their independence, safety, and quality of life.
  • Hearing changes with age : People who have intellectual disability and other developmental disabilities are not only living productive lives within communities across the country, but they are also living longer. Like others who reach their later years, older people with developmental disabilities are at risk for acquiring a number of age-related chronic conditions. One of the more common conditions among older adults is hearing loss. Regular hearing evaluations are important to identify losses in hearing that make it difficult for older adults to communicate in work, social and interpersonal situations.
  • Employment of people with intellectual disability : Based on the 1990 census, an estimated 6.2 to 7.5 million people in the United States have intellectual disability. Intellectual Disability is 12 times more common than cerebral palsy and 30 times more prevalent than neural tube defects such as spina bifida. It affects 100 times as many people as total blindness.

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  • Self-advocacy : For many people across the country and around the world, involvement in the self-advocacy movement has built self-confidence, supported self-determination, and provided opportunities for learning about and contributing to their communities and their countries.
  • National organizations involved in advocacy
  • The Arc: The Arc of the United States works to include all children and adults with cognitive, intellectual, and developmental disabilities in every community.
  • The Arc Mercer: Part of the mission of The Arc Mercer is to advocate for individuals with intellectual disability and/or developmental disabilities. By advocacy, we mean working for an individual to help enhance his or her quality of life, whether that means providing services and programs, training for employment within the community or helping to secure specific policies and programs that benefit them and their families.
  • Legal Rights of Persons with Intellectual Disability : From Texas-an example

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Assessing Individuals with Intellectual Disabilities

  • Newborn screening : Newborn screening identifies biochemical or other inherited conditions that may produce Intellectual Disabilities, other disabilities and/or death. Babies are screened for these conditions during the newborn period. These conditions are identified using tests on blood collected from a heel stick onto filter paper.
  • Psychiatric assessment for the person with intellectual disabilities: The psychiatrist who does not specialize in intellectual disabilities and developmental disabilities typically has had little or no exposure in medical school or residency training to the special diagnostic and therapeutic issues posed by this population,1 yet many psychiatrists will be called on, at some time, to evaluate and treat individuals with intellectual disabilities, often in crisis situations requiring emergency admissions or in inpatient facilities. It is essential, therefore, that psychiatrists acquire the basic tools needed for assessment and treatment planning at the interface of intellectual disability and psychiatric disorders.
  • Assessment and treatment: a vast resource of links on all topics of intellectual disabilities
  • Assessing children for the presence of a disability: This resource list provides school systems with information on assessment of school-aged children. The books and articles listed below may be useful to schools as they plan assessments of individual students to determine if they have a disability and, thus, are eligible for special education and related services.

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Assistive Technology


  • Assistive technology and intellectual disability: Assistive technology is the term used to describe devices used by people with intellectual disabilities and/or other disabilities that help compensate for functional limitations and increase learning, independence, mobility, communication, environmental control and choice. This term also refers to direct services that assist individuals in selecting, acquiring or using such devices.
  • Assistive technology with cognitive disabilities: over 50 great sites and links to assistive technology.

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Audio/Video Tapes

  • Newborn screening video tape: 1 OUT OF EVERY 1,500 BABIES born in the United States has a disorder detectable through newborn screening. To care for your youngest patients, and for their parents, it's important for you to be knowledgeable about newborn screening.

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Books and Publications

  • Intellectual Disabilities - Textbook.  Our purpose in writing the sixth edition of this text is to provide educators and other service providers with timely information about the many facets of intellectual disabilities from a life-cycle perspective. We have tried to digest the literature and add what we have learned from our own experiences. It is exciting to be involved in the area of intellectual disabilities, and we hope that our interest and enthusiasm about individuals who are intellectually disabled, their families, their friends, others with whom they come in contact, and the society in which they live come through in this book.
  • Psychiatric and Behavioral Disorders in Developmental Disabilities and Intellectual Disabilities - The problems faced by those with developmental disabilities are too often heightened by psychiatric or behavioral disorder. These quality of life issues have come to increasing attention over recent years of improved community and social integration.
  • Mental Retardation in America: A Historical Reader - Includes essays with a wide range of authors who approach the problems of intellectual disability from many differing points of view. This work is divided into five sections, each following in chronological order the major changes in the treatment of people classified as retarded.
  • Mental Retardation: A Lifespan Approach - Provides an introduction to intellectual disabilities that is readable and comprehensive, and which reflects the broad array of stories associated with this disability. The authors combine a developmental approach—discussing their subject as it evolves from birth to the elder years—with a multidisciplinary perspective that acknowledges the need for collaboration in regard to diagnosis and intervention in order to effectively assist people with mental retardation and their families.
  • Children with Mental Retardation: A Parent’s Guide - A book for parents of children with intellectual disability, whether or not they have a diagnosed syndrome or condition. It provides a complete introduction to a child's medical, therapeutic, and educational needs and covers topics such as family adjustment, daily care, child development, early intervention, special education, and legal rights.
  • Mental Retardation: Definition, Classification, and Systems of Supports - This book contains the most widely used definition of intellectual disability in the U.S. and is based on 10 years of use and research by a panel of 11 international experts. What is intellectual disability? How is it diagnosed? Can IQ scores alone determine if a person has intellectual disability? What is the cut-off IQ score when deciding whether a person has intellectual disability? Since the U.S. Supreme Court ruled to ban execution of persons with intellectual disability on June 22, 2002, states and courts grapple with these tough questions and more.
  • Handbook of Mental Retardation and Development - This book reviews theoretical and empirical work in the developmental approach to intellectual disability. Armed with methods derived from the study of typically developing children, developmentalists have recently learned about the intellectual disability child's own development in a variety of areas. These areas now encompass many aspects of cognition, language, social and adaptive functioning, as well as of maladaptive behavior and psychopathology.
  • Equal Treatment for People with Mental Retardation: Having and Raising a Child - Field, a Harvard law professor and author of Surrogate Motherhood (LJ 11/15/88), and civil liberties practitioner Sanchez provide a comprehensive examination of the reproductive and parental rights of intellectual disability citizens. After presenting an overview of mental retardation and of relevant public policy and case law, the authors detail current debates about procreation and parenting among the mentally retarded and put forth proposals to reform the existing system.
  • The Mental Retardation and Developmental Disability Treatment Planner - The Planner provides all the elements necessary to quickly and easily develop formal treatment plans that satisfy the demands of HMOs, managed care companies, third-party payers, and state and federal review agencies. Saves you hours of time-consuming paperwork, yet offers the freedom to develop customized treatment plans for the severely and persistently mentally ill.
  • Genetics and Mental Retardation: A New Look at behavior and Interventions - This book goes beyond mere description to advance a larger argument.  Simply put, we argue that genetic disorders affect various aspects of behavior, from cognition and language to adaptive and maladaptive behaviors.
  • The Kennedy Family and the History of Mental Retardation - According to Edward Shorter, just forty years ago the institutions housing people with intellectual disability had become a national scandal. The intellectually disabled who lived at home were largely isolated and a source of family shame. Although some social stigma still attaches to the people with developmental disabilities (a range of conditions including what until recently was called mental retardation), they now actively participate in our society and are entitled by law to educational, social, and medical services. The immense improvement in their daily lives and life chances came about in no small part because affected families mobilized for change but also because the Kennedy family made intellectual disability its single great cause.
  • Teaching Students with Mental Retardation: A Life Goal Curriculum Planning Approach - This book emphasizes and identifies (1) a prioritized life goal curriculum planning approach to identify the functional skills and concepts needed by a student with intellectual disability or severe disabilities to become as successful as possible in adult life, and (2) a diagnostic/prescriptive teaching approach to assess each students abilities and progress toward those individual life goals.
  • Teaching Students with Mental Retardation: Providing Access to the General Curriculum - Emphasis is on issues that arise in educating students with intellectual disability from preschool through secondary school...includes objectives, case studies, tips and photocopiable forms
  • Early Communication Skills for Children with Down Syndrome - Language, speech, and communication. You have heard the terms, and in general conversation, they are often used interchangeably.  But. they really have very distinct meanings.
  • Down Syndrome Quarterly - Down Syndrome Quarterly is an interdisciplinary journal devoted to advancing the state of knowledge on Down syndrome and will cover all areas of medical, behavioral, and social scientific research. It is published in March, June, September, and December and is distributed by subscription to individuals, organizations, and libraries.
  • Disability Solutions - Disability Solutions is the quarterly publication of Creating Solutions, a project of CIF of The San Francisco Foundation, a 501(c)(3) public charity, our fiscal sponsor.
  • Down Syndrome Amongst Us - A publication of information, and shared experience

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Causes of Intellectual Disability

  • Causes: Intellectual Disability can start anytime before a child reaches the age of 18 years.  It can be caused by injury, disease, or a brain abnormality.  These causes can happen before a child is born or during childhood.
  • Lead poisoning: Lead poisoning is one of the most common environmental child health problems in the United States and is caused by too much lead in the body. Lead is especially harmful to children younger than 6, but anyone who eats, drinks or breathes something which has too much lead can get lead poisoning.
  • PKU: PKU, which stands for Phenylketonuria, is an inherited metabolic disease (also called an inborn error of metabolism) that leads to intellectual disability and other developmental disabilities if untreated in infancy. With an inborn error of metabolism, the body is unable to produce proteins or enzymes needed to convert certain toxic chemicals into nontoxic products, or to transport substances from one place to another (Glanze, 1996).
  • Genetic issues: An introduction to genetics and intellectual disability
  • Overview, causes and risk factors: Causes of intellectual disability are numerous, but a specific reason for intellectual disability is determined in only 25% of the cases.

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  • Intellectual Disabilities-typical characteristics - A list of generalized characteristics of intellectual disabilities.  Please note that these are generalizations. There is a great deal of individual variation.
  • Characteristics of cognitive development - Cognitive development is defined as thinking, problem solving, concept understanding, information processing and overall intelligence. Many persons with fragile X syndrome have some cognitive weaknesses.

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Classifications/Types of Intellectual Disabilites

  • Prader-Willi - The ADA is civil rights legislation designed to protect people with intellectual or physical disabilities from discrimination based upon disability.
  • Reyes Syndrome - Reye's (pronounced "rye") syndrome is a disease which is believed to be caused by the ingestion of medicines (such as aspirin) that contain salicylate (pronounced "sa(LISS(a(late") that affects all organs of the body, but affects the liver and brain most lethally.
  • Fragile X - Many forms of intellectual disability are assumed to result from a disrupted or abnormal gene, but only a small fraction have been identified. Some genetic conditions, such as Down syndrome, are spontaneous abnormalities, whereas others are inherited, transmitted by carriers or affected individuals from one generation to another. Of the known genetic causes of intellectual disability, fragile X syndrome is currently considered the leading inherited cause, with an incidence between 1:2,500 and 1:4,000.

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Classroom Management


  • Problem solving skills training: Training in problem solving skills can be useful for persons with intellectual disability and mental illness who are likely to have problem solving deficits. Of special interest is training to improve social or interpersonal problem solving, in contrast to cognitive problem solving. Training in social problem solving is often part of cognitive-behavioral treatment "packages" such as Valenti-Hein and Mueser's Dating Skills Program and Benson's Anger Management Program.

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Definition of Intellectual Disabilitiy

  • What is intellectual disability -Intellectual Disability is characterized both by a significantly below-average score on a test of mental ability or intelligence and by limitations in the ability to function in areas of daily life, such as communication, self-care, and getting along in social situations and school activities. Intellectual Disability is sometimes referred to as a cognitive or intellectual more

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  • DSM diagnosis: A diagnosis of intellectual disability carries with it certain unique treatment needs that must be understood and addressed. Unfortunately, most psychiatrists are ill-equipped to handle this situation, having received little or no formal training in this area. This article is written with the specific goal of giving psychiatrists a better understanding of the special needs of patients with intellectual disability and strategies for improving their quality of life.

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Down Syndrome

  • Why it occurs - It wasn't until 1959 that Jerome Lejeune and Patricia Jacobs, working independently, first determined the cause to be trisomy (triplication) of the 21st chromosome. Cases of Down syndrome due to translocation and mosaicism (see definitions of these below) were described over the next three years.
  • Mosaic Down Syndrome - When a person has more than one type of chromosomal makeup, that is called mosaicism, like the mosaic style of art in which a picture is made up of different colors of tiles. In Down syndrome, mosaicism means that some cells of the body have trisomy 21, and some have the typical number of chromosomes.
  • Epilepsy and Down Syndrome - If you look at the population of all children with intellectual disability, there is a very large number (from 20 to 40%) that have epilepsy. The number is quite lower in Down Syndrome, but it's still a larger number than in the general population. Studies in the last two decades have estimated the number of people with DS who have seizures to be from 5 to 10%.
  • Pre-natal screening - Over the last 10 years, new technology has improved the methods of detection of fetal abnormalities, including Down syndrome. While there are ways to diagnose Down syndrome by obtaining fetal tissue samples by amniocentesis or chorionic villus sampling, it would not be appropriate to examine every pregnancy this way. Besides greatly increasing the cost of medical care, these methods do carry a slight amount of risk to the fetus. So screening tests have been developed to try to identify those pregnancies at "high risk." These pregnancies are then candidates for further diagnostic testing.
  • Adults with DS - Research has found that all adults with Down syndrome over the age of 40 develop plaques and tangles in their brains similar to those seen in persons with Alzheimer's disease. Based on this information, many parents and professionals often conclude that all persons with Down syndrome will eventually develop Alzheimer's disease. However, this conclusion is primarily based on autopsy data without a similar evaluation of premorbid clinical information. Many parent organizations are concerned that such conclusions may have deleterious effects if it is believed that all adults with Down syndrome eventually will be affected by Alzheimer's disease.
  • Occupational therapy - My intent with this article is to provide you with some information about how an occupational therapist (OT) may be able to help you and your child. Occupational therapists who work with children have education and training in child development, neurology, medical conditions, psychosocial development, and therapeutic techniques. Occupational therapists focus on the child's ability to master skills for independence.
  • Why physical therapy - As new parents of a child with Down syndrome, you already have your hands full just trying to get acclimated to this new country, to obtain the correct guidebooks and learn a few words of Dutch. Therefore, you are understandably skeptical when someone suggests that one of the new people you should meet is a physical therapist.
  • Speech/language therapy - Speech and language are complex and present many challenges to the child with Down syndrome that need to be addressed through a comprehensive approach to speech and language treatment. There have been major historical, legislative, and financial influences on speech and language services and service delivery for children with Down syndrome.
  • ADHD and DS - Attention deficit hyperactivity disorder, or ADHD, is a commonly diagnosed childhood problem. ADHD is characterized by consistent demonstration of the following traits: decreased attention span, impulsive behavior, and excessive fidgeting or other nondirected motor activity.   All children, including children with Down syndrome, display these traits from time to time. But the child with Down syndrome may exhibit these traits more often than other children his age.
  • Overview of DS 0-5 years - An overview of the development of babies and infants with Down syndrome from birth to five years. Includes a description of the uneven profile of expected development, identifying strengths in social understanding, self-help skills and behavior, and weaknesses in motor development and speech and language skills, the latter influenced by the high incidence of hearing loss, poor auditory processing and auditory memory skills.
  • Overview of DS 5-11 years - It is argued that the goals for children with Down syndrome should be age-appropriate and therefore many of the goals should be the same as for other children, although the child with Down syndrome may not achieve quite the same levels of competence in each area.
  • Overview of DS 11-16 years - Research studies demonstrate that young people with Down syndrome make significant progress in all areas of their development during their teenage years and into early adult life.
  • Living with DS - People with Down syndrome, whatever their age, are people first. They are people with abilities, strengths and weaknesses like everyone else. They may have additional needs but first they have the same needs as everyone else of their age group. The quality of health care, education and community support provided to children and adults with Down syndrome makes a real difference to their progress throughout life.
  • Down Syndrome:  Frequently Asked Questions - This page covers frequently-asked questions about Down syndrome, and is updated periodically.
  • National Down Syndrome Society - The National Down Syndrome Society envisions a world in which all people with Down syndrome have the opportunity to realize their life aspirations. NDSS is committed to being the national leader in enhancing the quality of life, and realizing the potential of all people with Down syndrome.
  • What is Down Syndrome? - A graphical/text informational introduction to Down syndrome.
  • Life Planning - Plan for life's transitions, from school to work to independent living. Also, because most people with DS are living into their fifties, sixties and beyond, it's Important to address future physical, social, financial and legal issues as early as possible.
  • Genetics and Down Syndrome - Down syndrome is a chromosomal condition that is associated with intellectual disability, a characteristic facial appearance, and poor muscle tone (hypotonia) in infancy. People with Down syndrome are at an increased risk for heart defects, digestive problems such as gastroesophageal reflux or celiac disease, and hearing loss.
  • Directories-Organizations by State - A graphical organization list.  Click on a state to find organizations in that state or fill in information below for more specific search results or to find an organization outside of the United States.
  • Down Syndrome: Caring for a Baby With Down Syndrome - Just like any other newborn, your baby will need to be fed, dressed, diapered, cuddled, held, talked to, played with and loved. However, your baby will probably have some health problems that will require some extra care.
  • Teaching Individuals with Down Syndrome - Children born with Down syndrome may be mild to severely disabled, making it difficult to generalize best education practices for these individuals. But commonalities do exist. The following list outlines some typical features of Down syndrome.

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Fragile X Syndrome

  • What is Fragile X Syndrome? - Fragile X is a family of genetic conditions, which can impact individuals and families in various ways. These genetic conditions are related in that they are all caused by gene changes in the same gene, called the FMR1 gene.
  • What is Fragile X? - A graphic/textual informational page on Fragile X.
  • Fact Sheet - Fragile X syndrome is the most common inherited form of intellectual disability. It affects about 1 in 4,000 males and 1 in 8,000 females and occurs in all racial and ethnic groups.
  • How is Fragile X Syndrome Inherited? - Many inherited diseases like sickle cell and hemophilia are caused by a single change in the genetic code in the DNA.  It is as if there is a single typographical error in the instructions for how to make the protein.  Fragile X syndrome is not the result of a single change in a base.  Instead it is known as a trinucleotide repeat disorder.
  • Characteristics of Fragile X Syndrome - Males and females exhibit quite different physical, cognitive, behavioral, sensory, speech and language impacts of fragile X syndrome. In general, females with fragile X either do not have the characteristics seen in males, or the characteristics show up in a milder form.
  • Genetic Testing for Fragile X Syndrome - Genetic testing for Fragile X should be considered in, but not limited to, the following indications: 1. Children (males and females) with developmental, speech, language or motor delay...
  • Intervention for Problems Associated With Fragile X Syndrome - While there is no cure for fragile X syndrome as yet, there are many areas of intervention that can improve the lives of those affected and their families. All persons with fragile X can make progress, given the proper education, therapy, and support.
  • Medical Follow-up and Pharmacotherapy - The physician who follows children and adults with fragile X syndrome (FXS) must be familiar with the physical and behavioral problems associated with this disorder to provide optimal treatment and intervention. Although a cure does not presently exist, a variety of effective interventions are available. In the future, gene therapy or protein replacement therapy will be a reality.
  • What is the Cause of Fragile X Syndrome? - What is the biological cause of fragile X syndrome? There are several ways we can answer that question.
  • Education - Children whose development is affected by fragile X syndrome are eligible for special education services. The Individuals with Disabilities Education Act (IDEA), a federal law, mandates a free, appropriate public education in the least restrictive environment (that is, as much as possible with non-disabled children) for all children with special needs.
  • Books and videos on Fragile X - The following is a list of resources available from the Foundation. Please see the order form for prices and ordering instructions.
  • Families and Fragile X Syndrome - Finding out that your child, a member of your family, or a friend has a “syndrome” can raise some tough questions. What does having that syndrome mean for the individual? What special needs will this individual have? How will those needs affect my family? Will my child, family member, or friend be able to take part in everyday activities and important events?

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Frequently Asked Questions

  • FAQ - This page covers frequently-asked questions about Down syndrome, and is updated periodically.
  • Fact sheet - Intellectual Disability is a term used when a person has certain limitations in mental functioning and in skills such as communicating, taking care of him or herself, and social skills. These limitations will cause a child to learn and develop more slowly than a typical child. Children with intellectual disability may take longer to learn to speak, walk, and take care of their personal needs such as dressing or eating. They are likely to have trouble learning in school. They will learn, but it will take them longer. There may be some things they cannot learn.

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History of the Field

  • History of events - A Very Brief Run Through of Some Significant Historical Perspectives, People, and Events Freely adapted from A History of Intellectual Disability, R.C. Scheerenberger, Brookes Publishing Co. (Baltimore, 1983).

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Kleinfelter's Syndrome

From the National Institutes of Health (Kleinfelter's Syndrome)

Diagnosis/Symptoms (Kleinfelter's Syndrome)

  • Testosterone Test (American Association for Clinical Chemistry) - Testosterone testing is used to diagnose several conditions in men, women, and boys. These conditions include: delayed or precocious (early) puberty (boys);  decreased sex drive (men); erectile dysfunction (men); infertility (men and women); testicular tumors (men); and  excessive body hair, also called hirsutism, and masculinization, also called virilization (women).

Clinical Trials- (Kleinfelter's Syndrome)

Specific Conditions (Kleinfelter's Syndrome)

  • Patient's Guide to Low Testosterone (Endocrine Society, Hormone Foundation) - It is estimated that four to five million American men may not produce enough testosterone. Most discouraging, research finds that most men know very little about testosterone, the potential consequences of having low testosterone levels, and the availability of therapies to increase testosterone and overall health.
  • Sex Chromosome Variations: About 47XXY (Klinefelter Syndrome and Associates) - Klinefelter Syndrome is probably the most common chromosomal variation found in humans. In random surveys, it is found to appear about once in every 500 to one in every 1,000 live born males. Since the largest percentage of these men would have never been diagnosed otherwise, it shows that in many cases affected individuals lead healthy, normal lives with no particular medical or social questions.

Genetics (Kleinfelter's Syndrome)

  • Genetics Home Reference: Klinefelter syndrome (National Library of Medicine) - Kleinfelter syndrome is a chromosomal condition related to chromosomes X and Y. People typically have two sex chromosomes in each cell; females have two X chromosomes, and males have one X chromosome and one Y chromosome. Klinefelter syndrome is caused by the presence of one or more extra copies of the X chromosome in a male's cells. Extra copies of genes on the X chromosome interfere with male sexual development, preventing the testicles from functioning normally and reducing the levels of testosterone.


  • Chromosomal Abnormalities (March of Dimes Birth Defects Foundation) - About 1 in 200 babies is born with a chromosomal abnormality. Down syndrome, in which a baby is born with an extra chromosome 21, is among the most common chromosomal abnormalities, and the one whose effects are familiar to most people. Children with Down syndrome have varying degrees of intellectual disability, characteristic facial features and, often, heart defects and other problems.

Organizations (Kleinfelter's Syndrome)

  • Klinefelter Syndrome and Associates - Founded in 1989, KS&A is the nation’s oldest and leading 501 (c)(3) nonprofit organization dedicated to enhancing the lives of individuals and families living with X and Y chromosome variations (or aneuploidies).
  • National Institute of Child Health and Human Development - The National Institute of Child Health and Human Development (NICHD) is part of the National Institutes of Health National Institutes of Health, the biomedical research arm of the U.S. Department of Health and Human Services. The mission of the NICHD is to ensure that every person is born healthy and wanted, that women suffer no harmful effects from reproductive processes, and that all children have the chance to achieve their full potential for healthy and productive lives, free from disease or disability, and to ensure the health, productivity, independence, and well-being of all people through optimal rehabilitation.

Teenagers (Kleinfelter's Syndrome)

  • Delayed Puberty (Nemours Foundation) - There are several reasons why puberty may be delayed. Most often, it's simply a pattern of growth and development in a family. A guy or girl may find that his or her parent, uncle, aunt, brothers, sisters, or cousins developed later than usual, too. This is called constitutional delay (or being a late bloomer), and it usually doesn't require any kind of treatment. These teens will eventually develop normally, just later than most of their peers.
  • Information from the Medical Encyclopedia on Klinefelter's Syndrome - Humans have 46 chromosomes, which contain all of a person’s genes and DNA. Two of these chromosomes, the sex chromosomes, determine a person’s gender. Both of the sex chromosomes in females are called X chromosomes. (This is written as XX.) Males have an X and a Y chromosome (written as XY). The two sex chromosomes help a person develop fertility and the sexual characteristics of their gender...

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Medical Issues/Medications

  • Metabolism and DS - Research suggests children with Down syndrome are as active as their peers, yet use fewer calories overall. They appear to have a lowered Basal Metabolic Rate, which is the rate a person burns calories for fuel when completely at rest - or sleeping. This means that children with Down syndrome use less energy when they are resting or sleeping.
  • Dermatological disorders and DS - Since the skin tends to reflect other conditions of the body, it's not surprising that children and adults with DS have more than their share of skin problems. This article will address those skin conditions and disorders that are more common in people with DS than the general population.
  • Blood disorders and DS - In children and adults with DS, it is common to see red blood cells that are larger than normal; this is called macrocytosis. This has been speculated to be due to an altered folate metabolism seen in Down syndrome, along with structural changes in the red cell membrane. Unless accompanied by anemia, macrocytosis does not require treatment.
  • Celiac disease and DS - Studies in the 1990s indicated that children with DS are at a higher risk to develop CD than the general population. The reasons for that aren't entirely clear, but since children with DS are at a greater risk from auto-immune diseases, that CD represents another one of these type of diseases.
  • Obstructive sleep apnea - Children with Down syndrome (DS) are certainly at risk for OSA. In 1991, one study showed 45% had OSA. This can be caused by several different factors present in DS: the flattened midface, narrowed nasopharyngeal area, low tone of the muscles of the upper airway and enlarged adenoids and/or tonsils.
  • Gastrointestinal issues - The gastrointestinal (GI) tract is made up of the body parts and organs that take in food, extract the nutrients, and get rid of the wastes. This includes the mouth, throat, esophagus, stomach, small and large intestines as well as the rectum. The salivary glands, pancreas and the liver add enzymes as well as other substances to help the GI tract to digest and absorb the nutrients.
  • Heart defects - Around 40-45 percent of all babies born with DS are born with some form of a heart defect. As mentioned these defects usually led to death. But advances in cardiac surgery as made it possible to repair most defects. Let me start with A general overview of the heart before I get into the actual defects that can occur.<font face="Arial" size="2"></font>
  • Genetic testing - PFD file.  The international Human Genome Project, an effort to map all the genes within our bodies, has greatly expanded our ability to test for the potential presence of certain diseases that can result in various disorders and conditions, such as intellectual disability. This rapid increase in genetic technology is outpacing our ability to develop treatments to correct these diseases and conditions. A growing list of disease-causing genes has been identified, enabling an otherwise healthy individual to know whether or not he or she will develop a disorder or possibly pass a disease gene on to his or her children. This is the first time in history that such specific, predictive genetic information has been available. How will having this information impact society? Do most of us want to know about future genetic information that could change our lives?
  • Myths - PFD file.  Intellectual disability means that a person develops mentally at a below average rate. They may have difficulty in learning and social adjustment. But they can learn. With the appropriate intervention and education, they can lead satisfying and productive lives in the community.
  • Genetic discrimination - PFD file.  Discrimination based on the presence of a disability has always been an issue of great concern to The Arc. People with intellectual disability have, for example, long been discriminated against in both insurance and employment. Now a different type of discrimination is emerging due to the increasing use of genetic testing for the purpose of exposing the presence of any abnormal or defective genes. This new phenomenon is called genetic discrimination.
  • Gene therapy - PFD file.  Gene therapy is an experimental treatment in which normal genes are introduced into the body’s cells in order to correct or modify the function of the cell which is not working. The initial purpose of gene therapy was to treat hereditary diseases by adding good genes to function for missing or defective genes. Researchers soon discovered that genes could also be introduced into cells to help patients fight disease.

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  • National Down Syndrome Congress - We made a radical shift, from isolating people with disabilities to bringing them into our communities. Suddenly, people who had been excluded, invisible, became part of daily life. Some strode as adults from the abyss of large group homes into community settings. Others made more mundane entries – they were born to families whose intent was – simply – to love them.
  • National Down Syndrome Society Web Site - The National Down Syndrome Society envisions a world in which all people with Down syndrome have the opportunity to realize their life aspirations. NDSS is committed to being the national leader in enhancing the quality of life, and realizing the potential of all people with Down syndrome.
  • International Mosaic Down Syndrome Association - Welcome to the International Mosaic Down Syndrome Associations website. We hope that by finding us, you'll be able to contact other families, and join our circle of friends and support.
  • The Arc - The Arc of the United States advocates for the rights and full participation of all children and adults with intellectual and developmental disabilities. Together with our network of members and affiliated chapters, we improve systems of supports and services; connect families; inspire communities and influence public policy.
  • AAIDD - AAIDD promotes progressive policies, sound research, effective practices, and universal human rights for people with intellectual and developmental disabilities.
  • TASH - TASH is an international association of people with disabilities, their family members, other advocates, and professionals fighting for a society in which inclusion of all people in all aspects of society is the norm.
  • CEC - The Council for Exceptional Children (CEC) is the largest international professional organization dedicated to improving educational outcomes for individuals with exceptionalities, students with disabilities, and/or the gifted. CEC advocates for appropriate governmental policies, sets professional standards, provides continual professional development, advocates for newly and historically underserved individuals with exceptionalities, and helps professionals obtain conditions and resources necessary for effective professional practice.

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Overview of Intellectual Disability

  • Symptom and a syndrome - Feeblemindedness and mental deficiency were used as labels during the later part of the last century and in the early part of this century. Consistent across all definitions are difficulties in learning, social skills, everyday functioning, and age of onset (during childhood). Intellectual disability has also been used as a defining characteristic or symptom of other disorders such as Down syndrome and Prader-Willi syndrome.
  • Fact sheet on ID - Intellectual Disability is a term used when a person has certain limitations in intellectual functioning and in skills such as communicating, taking care of him or herself, and social skills. These limitations will cause a child to learn and develop more slowly than a typical child.
  • Children with ID - Most children with intellectual disability can learn a great deal, and as adults can lead at least partially independent lives. Most individuals with intellectual disability have only the mild level of intellectual disability. Intellectual disability may be complicated by several different physical and emotional problems. The child may also have difficulty with hearing, sight or speech.

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Parent Information

  • Toilet training - The process of teaching a child to use the toilet can be a frustrating one. This is especially true if the child has a developmental disability. The protocol listed below has been used successfully, with individuals with developmental disabilities of all ages.
  • Issues of sexuality - As human beings, individuals with Down syndrome have the right to emotionally satisfying and culturally appropriate sexual expression. As patients, they have the right to routine reproductive health care provided to the general population. Cognitive and language disabilities may predispose this population to unwanted pregnancy, sexually transmitted disease, and sexual exploitation. Sex education tailored to cognitive level, learning style, and living arrangements is essential to the education of children and young adults with Down syndrome.
  • Respite care - "Respite" refers to short term, temporary care provided to people with disabilities in order that their families can take a break from the daily routine of caregiving. Unlike child care, respite services may sometimes involve overnight care for an extended period of time.
  • Sibling issues - Children who grow up together in the same family can form a unique bond, regardless of a brother or sister having a disability. In fact, the relationship between siblings and their brother or sister with a disability can be identical to the relationship between any brother or sister. They may be close and remain so into adulthood, or they may never develop a close relationship or grow apart as they get older.

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Prader-Willi Syndrome

From the National Institutes of Health (Prader-Willi Syndrome)

Overviews (Prader-Willi Syndrome)

Clinical Trials (Prader-Willi Syndrome)

Nutrition (Prader-Willi Syndrome)

  • Prader-Willi Food Pyramid (Prader-Willi Syndrome Association) - The Food Pyramid Guide to Daily Food Choices, designed by the U.S. Department of Agriculture for adults who need 1,600 to 2,800 calories a day, represents the relative portions of foods to eat each day to maintain a healthy weight and body. To make the Food Pyramid usable for people with Prader-Willi syndrome, a few changes have to be made.

Related Issues (Prader-Willi Syndrome)

  • Patient's Guide to Low Testosterone (Endocrine Society, Hormone Foundation) - It is estimated that four to five million American men may not produce enough testosterone. Most discouraging, research finds that most men know very little about testosterone, the potential consequences of having low testosterone levels, and the availability of therapies to increase testosterone and overall health.

Genetics (Prader-Willi Syndrome)

  • Genetics Home Reference: Prader-Willi syndrome (National Library of Medicine) - Prader-Willi syndrome is a complex genetic condition that affects many parts of the body. In infancy, this condition is characterized by weak muscle tone (hypotonia), feeding difficulties, poor growth, and delayed development. Beginning in childhood, affected individuals develop an insatiable appetite and chronic overeating (hyperphagia), obesity, and short stature.
  • Genetics of Prader-Willi Syndrome: An Explanation for the Rest of Us (Prader-Willi Syndrome Association) - When the medical world first learned about Prader-Willi syndrome in 1956, doctors had no idea what caused people to have this collection of features and problems that we now know as PWS. In 1981, Dr. David Ledbetter and his colleagues reported a first breakthrough discovery: Many people with PWS that they studied had the same segment of genes missing from one of their chromosomes. They had discovered the deletion on chromosome 15 that accounts for about 70 percent of the cases of PWS. Since then, researchers have made a series of other important discoveries about the genes involved in Prader-Willi syndrome.


Organizations (Prader-Willi Syndrome)

  • National Institute of Child Health and Human Development - The mission of the NICHD is to ensure that every person is born healthy and wanted, that women suffer no harmful effects from reproductive processes, and that all children have the chance to achieve their full potential for healthy and productive lives, free from disease or disability, and to ensure the health, productivity, independence, and well-being of all people through optimal rehabilitation.
  • Prader-Willi Syndrome Association - Prader-Willi Syndrome Association (USA) is dedicated to serving individuals affected by Prader-Willi syndrome (PWS), their families, and interested professionals.

Information from the Medical Encyclopedia (Prader-Willi Syndrome)

  • Prader-Willi Syndrome - Prader-Willi syndrome is a congenital (present from birth) disease characterized by obesity, decreased muscle tone, decreased mental capacity, and hypogonadism...

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  • How common - Intellectual disability is characterized both by a significantly below-average score on a test of intellectual ability or intelligence and by limitations in the ability to function in areas of daily life, such as communication, self-care, and getting along in social situations and school activities. Intellectual disability is sometimes referred to as a cognitive or intellectual disability.

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Turner Syndrome

From the National Institutes of Health (Turner Syndrome)

  • Clinical Features of Turner Syndrome (National Institute of Child Health and Human Development) - Turner syndrome affects approximately 1 out of every 2,500 female live births worldwide. It embraces a broad spectrum of features, from major heart defects to minor cosmetic issues. Some individuals with Turner syndrome may have only a few features, while others may have many. Almost all people with Turner syndrome have short stature and loss of ovarian function, but the severity of these problems varies considerably amongst individuals.

Overviews (Turner Syndrome)

Clinical Trials (Turner Syndrome)

Genetics (Turner Syndrome)

  • Genetics Home Reference: Turner syndrome - Turner syndrome is a chromosomal condition that affects development in females. Women with this condition tend to be shorter than average and are usually unable to conceive a child (infertile) because of an absence of ovarian function. Other features of Turner syndrome can include extra skin on the neck (webbed neck), puffiness or swelling (lymphedema) of the hands and feet, skeletal abnormalities, heart defects, and kidney problems. Developmental delays, learning disabilities, and behavioral problems are also possible, although these characteristics vary among affected females.

Organizations (Turner Syndrome)

  • National Institute of Child Health and Human Development - The mission of the NICHD is to ensure that every person is born healthy and wanted, that women suffer no harmful effects from reproductive processes, and that all children have the chance to achieve their full potential for healthy and productive lives, free from disease or disability, and to ensure the health, productivity, independence, and well-being of all people through optimal rehabilitation.
  • Turner's Syndrome Society of the United States - From its beginning, and with an uncompromising effort, the Society determined to encourage medical research, the dissemination of state-of-the-art TS information, and social support services to individuals, families, physicians and the general public.

Children (Turner Syndrome)

  • Turner Syndrome (Nemours Foundation) - Turner syndrome results from a chromosomal abnormality in which a female infant is born with only one X chromosome (instead of the usual two) or is missing part of one X chromosome. In most cases, untreated females with this disorder are typically short in stature (average final adult height is 4 feet 7 inches [140 centimeters]) and may have a variety of associated physical features and medical problems.

Teenagers (Turner Syndrome)

  • Turner Syndrome (Nemours Foundation) - Girls with Turner syndrome usually have normal intelligence, but some may experience learning difficulties, particularly in mathematics. Many also have a problem with tasks requiring spatial skills, such as map reading or visual organization. Hearing problems are also more common in girls with Turner syndrome.

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William Syndrome

  • The William Syndrome Comprehensive Web Site - The Williams Syndrome Foundation (WSF) seeks to create or enhance opportunities in education, housing, employment and recreation for people who have Williams Syndrome and other related or similar conditions. The WSF identifies, initiates, funds and provides strategic guidance for major, long-range development projects, either by itself, or by cooperating with other organizations.

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