Common Causes of Intellectual Disabilities

1. Common Causes of Intellectual Disabilities Dianne Blevons Eastern Connecticut State University ECE505- Young Children with Special Needs Dr. Ann Gruenberg July 25, 2013

2. What causes intellectual disability? Anything that interferes with normal brain development can trigger an intellectual disability. • Genetic conditions- caused by absence of genes or too much replication of gene code. Examples include Down syndrome and Fragile X Syndrome. • Problems during pregnancy- Poor health including alcohol or drug use, malnutrition, certain infections, or preeclampsia can affect fetal brain development. • Problems during childbirth- Intellectual disability may result if a child is deprived of oxygen during childbirth or born extremely premature. • Illness or injury- infections such as meningitis, whooping cough, or measles can lead to intellectual disability in the developing child. Severe head injury, near drowning, exposure to toxic substances like lead, and severe neglect can also dramatically impact brain development.

3. Prevalent Types of Intellectual Disability • Down Syndrome ( extra genetic material) • Fragile X Syndrome ( gene mutation and replication ) • Klinefelter’s Syndrome (extra genetic material) • Williams Syndrome (missing genetic material) • Cretinism (congenital thyroid hormone deficiency)

4. Down Syndrome • Occurs when there is an extra copy of chromosome 21. The extra chromosome causes problems with the way the body and brain develop. • Down syndrome is one of the most common causes of human birth defects and is present in all cultures. • Physical development is often slower than normal. • Most children with Down syndrome never reach their average adult height. • Children may also have delayed mental and social development. • Common problems include : • -Impulsive behavior • -Poor judgment • -Short attention span • -Slow learning • As they grow and become aware of their limitations, they may also feel frustration and anger. • Early intervention and special education help children adapt and gain greater independence. • Generally need some degree of supervision through lifetime. Very dependent on life-long family or group home type care arrangements.

5. Fragile X Syndrome •  FXS is caused by changes in the fragile X mental retardation 1 (FMR1) gene. It occurs in all races and ethnicities. • The FMR1 gene usually makes a protein called fragile X mental retardation protein (FMRP). FMRP is needed for normal brain development. • People who have FXS do not make this protein. People who have other fragile X-associated disorders have changes in their FMR1 gene but usually make some of the protein • Symptoms • Both boys and girls can share certain physical, behavioral and intellectual traits. …not everyone has the same characteristics to the same degree. • Often difficult to diagnose : symptoms mimic other disorders, such as Autism, Prader-Willisyndrome and developmental delays. • Physical characteristics • Males with fragile X : • prominent ears, a long and narrow face, flat feet, large testicles after • puberty, and very flexible finger joints. • Females with fragile X : Often similar physical characteristics, though they are often less distinctive.

6. Fragile X Syndrome - Continued • Intellectual and behavioral characteristics • Males with fragile X may show: • -delayed speech • -delayed motor skills • -repetitive and unclear speech • -hyperactivity and short attention spans • -Autistic-like features, including poor eye contact, hand biting, hand flapping and • hypersensitivity to environment (such as noise and crowds) • Females may also show the above symptoms and/or distinct characteristics, including: • -learning difficulties • -short attention span • -shyness • -social anxiety • Many problems, particularly the emotional ones, lessen as children get older. • While there is currently no cure, there are many areas of treatment and intervention that can improve the lives of affected individuals and their families. Given the proper education, therapy, and support, all persons with this syndrome can make progress.

7. Klinefelter’s Syndrome • Klinefelter syndrome is one of the most common chromosomal abnormalities. About 1 in every 500 to 800 males is born with this disorder. • This condition occurs in males where one or more extra X chromosomes are present. • Boys with this condition appear normal at birth. • By mid puberty, affected boys have low levels of testosterone causing development of female breast tissue, small testicles ,and the inability to make sperm(consequently sterile). • Affected males may also have learning disabilities , so special education or tutoring may benefit. • High incidence of behavior problems such as shyness and immaturity are reported among these males. • Boys with this syndrome an increased risk for anxiety, depression, gender-identity confusion, and difficulty maintaining relationships. Counseling offers necessary support to these boys and their families. • Klinefelter’s babies are more likely to be born to older mothers. There is no cultural prevalence as it not genetically passed on.

8. William’s Syndrome • People from all cultures are affected by this syndrome. • Children with the syndrome are missing genetic material from chromosome 7. • A deletion is caused by a break in the DNA molecule that makes up a chromosome. In most cases, the chromosome break occurs while the sperm or egg is developing. • When this “broken” cell is fertilized, the child will develop Williams syndrome. • Frequent issues for children with this disorder: • -cardiovascular disease • -developmental delays and late milestone achievement • -mild to severe learning disabilities.  • -Highly distractible (which often improves with age) • Often have striking verbal abilities, highly social personalities and a flair for music. • No difficulty getting attached- families often report that they are especially close and fond of their social and outgoing William’s children. .

9. Cretinism or Congenital Hypothyroidism • A affected person exhibits severely stunted physical and mental growth due to untreated congenital deficiency of thyroid hormones. • Prevalent in many cultures deprived of appropriate dietary iodine (Often linked to impoverished populations). • General lack of hormone caused by maternalnutritional deficiency of iodine. • Getting diagnosed early usually leads to a good outcome. • Newborns who are diagnosed and treated in the first month or so usually have normal intelligence. • Untreated mild hypothyroidism can lead to severe intellectual disability and growth problems. • A lack of thyroid hormone can cause damage that cannot be reverseddue to lack of central nervous system development.

10. Early Intervention and Family Support • All cases of intellectual disability benefit from early intervention to aid both the developing child and the family system. • Since each child is a unique individual case, s/he will require an array of different services including: • -Educational intervention • -Speech therapy, physical therapy, and/or occupational therapy • -Mental heath services regarding social/emotional development and • ecological impact of the child on the family system. • -Appropriate nutrition guidance, medical care, and supervision of • health issues specifically related to the diagnosis. • -financial support regarding cost of services or undergirding basic needs of • a monetarily challenged family situation.

11. References: Congenital hypothyroidism (Cretinism). (n.d.). Congenital Hypothyroidism (Cretinism). Retrieved from http://www.virtualmedicalcentre.com/diseases/congenital-hypothyroidism-cretinism/328 Congenital hypothyroidism. (n.d.). - Genetics Home Reference. Retrieved from http://ghr.nlm.nih.gov/condition/congenital-hypothyroidism Cretinism. (n.d.). Cretinism. Retrieved from http://www.e-radiography.net/radpath/c/cretinism.htm Dierssen, M., & de la Torre Fornell, R. (2012). Down syndrome. Burlington: Elsevier Science. Down syndrome. (n.d.). - Genetics Home Reference. Retrieved from http://ghr.nlm.nih.gov/condition/down-syndrome Facts About Down Syndrome. (n.d.). National Association for Down Syndrome. Retrieved July 25, 2013, from http://www.nads.org/pages_new/facts.html Fernández Carvajal, I., Aldridge, D., & ebrary, I. (2011). Understanding fragile X syndrome. London ; Philadelphia: Jessica Kingsley Publishers. Fragile X Syndrome. (n.d.). National Fragile X Foundation RSS. Retrieved July 25, 2013, from http://www.fragilex.org/fragile-x-associated-disorders/fragile-x-syndrome/ Goldstein, S., & Reynolds, C. (2010). Handbook of neurodevelopmental and genetic disorders in children, 2e (2nd ed.). New York: Guilford Press.

12. Hodapp, R. M. (2012). International review of research in developmental disabilities. Burlington: Elsevier Science. Klinefelter syndrome. (n.d.). - Genetics Home Reference. Retrieved from http://ghr.nlm.nih.gov/condition/klinefelter-syndrome Learning About Klinefelter Syndrome. (n.d.). Learning About Klinefelter Syndrome. Retrieved from http://www.genome.gov/19519068 Photo Credit- “Children playing with parachute” by Wendy Bland. Retrieved from http://www.st-marks-toddler-playgroup.org Westwood, P. (2013). Learning and learning difficulties. Hoboken: Taylor and Francis. Williams Syndrome - Salk Institute. (n.d.). Williams Syndrome - Salk Institute. Retrieved from http://www.salk.edu/ra/williams_syndrome.html WILLIAMS SYNDROME. (n.d.). Williams Syndrome. Retrieved from http://learn.genetics.utah.edu/content/disorders/whataregd/williams/