2. Causes of Developmental Disabilities
• Congenital – a problem present at birth
• Nature and nurture – work together to “determine developmental
outcomes”
• Check out the prenatal developmental chart on p. 101 in your text!
• Biological insult – may or may not cause a developmental problem
• Genetic disorders – are present at birth, but are not necessarily
hereditary
• Most single-gene disorders – both parents are healthy carriers of an
abnormal gene. Each pregnancy has a 25% potential outcome of the
child having the disorder
3. Syndromes
• Down Syndrome – Trisomy 21; probably the most well-known cause
of intellectual disabilities
• Common characteristics described on p. 103
• Many children with Down syndrome also have health issues such as heart
defects
• Fragile X syndrome- like Down syndrome, a chromosomal
abnormality.
• The most common inherited cause of intellectual disabilities in the U.S.
• More likely to impact boys more severely
4. Metabolic and Gene Disorders
• PKU – phenylketonuria
• Every newborn in the U.S. is screened with a simple blood test following birth
• Dietary changes can prevent irreversible brain damage
• Tay Sachs – most likely to occur in people of Eastern European Jewish
descent
• Cystic Fibrosis – fatal physical disorder that does not interfere with mental
development; children are now living into adulthood with this disease
• Sickle-cell anemia – serious health disorder that primarily affects AfricanAmerican
• Duchenne Muscular Dystrophy – fatal muscular disease that occurs in
males
5. Prenatal Infections and Intoxicants
• Many are listed in your text on p. 105
• Better prenatal care has improved outcomes in recent years, but
pregnancy is not without its risks
• FAE and FAS – the #1 preventable cause of intellectual disabilities
• Poor nutrition – sadly, this is still an issue with pregnant women,
particularly teenage mothers.
6. Other Complications
• Birth – CP (cerebral palsy) may result from lack of oxygen during birth
• Post-natal diseases and illnesses
• Lead poisoning – still a huge problem, particularly in high poverty
areas
• Poverty – increased risk factors including
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Nutritional deficiency
Lack of good healthcare and education
Homelessness
Single parent families
Lack of quality childcare – may even be detrimental to child’s development
7. Classifications of Developmental
Disabilities
• SLD – specific learning disabilities – categorized by normal or above
normal IQ, but discrepancies in ability to read, write, or do math as
compared to IQ
• Speech and language problems – may or may not accompany other
developmental disorders
• Intellectual disabilities (mental retardation) – MR is now considered a
more offensive term
• Emotional disorders (ED or BED) – behavior or emotional responses
are not age or developmentally typical and interfere with normal
functioning in education, social, or vocational settings
8. Classifications of Developmental
Disabilities (cont.)
• Multiple disabilities – more than one disability
• Hearing loss – “deafness” or “hard of hearing”
• Orthopedic impairments – may include congenital impairments such
as absence of a limb or paralysis; impairments caused by diseases
such as polio; neurological or spinal cord damage causing problems
such as paralysis as in spina bifida; impairments caused by injury or
other causes
• Health impairments – heart, cancers, chronic diseases
(asthma, diabetes, CF), etc.
9. Classifications of Developmental
Disabilities (cont.)
• Visual impairments – blind; partially sighted
• Deaf/blind – multisensory disorder
• Autism – a developmental disorder of the brain that is behaviorally
defined along a spectrum. Some cognitive delay is present in about ¾
of the children with autism
• TBI – Traumatic brain injury
