• Chromosomal disabilities such as Down Syndrome, Mosaic Trisomy 16, Fragile X, Klinefelter Syndrome (XXY), Cri-du-chat Syndrome, Angelman Syndrome, etc.
  • Some endocrine abnormalities such as Prader Willi, Cushing’s Syndrome, hypothyroidism, PKU, for example. More than 3,000 different congenital abnormalities are known.

Prenatal Injuries

  • Infections (Rubella, CMV)
  • Poor maternal nutrition
  • Alcohol/drug use: Fetal Alcohol Syndrome/Spectrum Disorder (FAS, FASD)
  • Errors in development such as: Spina bifida, cleft palate, microcencephaly, macroencephaly, other neural-tube defects (may be caused or complicated by folic acid deficiency, undiagnosed diabetes, and/or unknown environmental exposures);
  • Autism (maybe)

At Birth

  • Oxygen deprivation related brain damage
  • Brain injury from forceps/difficult deliveries (Cerebral Palsy, seizure disorders, etc)

Postnatal (after birth)

  • Shaken Baby Syndrome
  • Head or Traumatic Brain Injury
  • Drowning
  • Infections
  • Lead, mercury, alcohol, other poisoning
  • Huffing of chemical inhalants, paint, glue, etc. (by children under age 22)

Unknown Causes

  • Autism Spectrum Disorder & other Pervasive Developmental Disorders
  • Other neurological issues such as Tourette Syndrome, ADHD, and early dementia which are not well understood may sometimes be associated with people in I/DD services, but are not considered to be developmental disabilities alone.