Autism risk factors
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Risk Factors
The risk of autism is associated with several prenatal and perinatal risk factors. A 2007 review of risk factors found associated parental characteristics that included advanced maternal age, advanced paternal age, and maternal place of birth outside Europe or North America, and also found associated obstetric conditions that included low birth weight and gestation duration, and hypoxia during childbirth.[1]
Associated Conditions
Autism is associated with several other conditions:
- Genetic disorders. About 10–15% of autism cases have an identifiable Mendelian (single-gene) condition, chromosome abnormality, or other genetic syndrome,[2] and ASD is associated with several genetic disorders.[3]
- Mental retardation. A 2001 British study of 26 autistic children found about 30% with intelligence in the normal range (IQ above 70), 50% with mild to moderate retardation, and about 20% with severe to profound retardation (IQ below 35). For ASD other than autism the association is much weaker: the same study reported about 94% of 65 children with PDD-NOS or Asperger's had normal intelligence.[4]
- Maleness. Boys are at higher risk for autism than girls. The ASD sex ratio averages 4.3:1 and is greatly modified by cognitive impairment: it may be close to 2:1 with mental retardation and more than 5.5:1 without.[5]
- Epilepsy, with variations in risk of epilepsy due to age, cognitive level, and type of language disorder.[6]
- Several metabolic defects, such as phenylketonuria, are associated with autistic symptoms.[7]
References
- ↑ Kolevzon A, Gross R, Reichenberg A (2007). "Prenatal and perinatal risk factors for autism". Arch Pediatr Adolesc Med. 161 (4): 326–33. PMID 17404128.
- ↑ Folstein SE, Rosen-Sheidley B (2001). "Genetics of autism: complex aetiology for a heterogeneous disorder". Nat Rev Genet. 2 (12): 943–55. doi:10.1038/35103559. PMID 11733747.
- ↑ Zafeiriou DI, Ververi A, Vargiami E (2007). "Childhood autism and associated comorbidities". Brain Dev. 29 (5): 257–72. doi:10.1016/j.braindev.2006.09.003. PMID 17084999.
- ↑ Chakrabarti S, Fombonne E (2001). "Pervasive developmental disorders in preschool children". JAMA. 285 (24): 3093–9. PMID 11427137.
- ↑ Invalid
<ref>tag; no text was provided for refs namedNewschaffer - ↑ Levisohn PM (2007). "The autism-epilepsy connection". Epilepsia. 48 (Suppl 9): 33–5. PMID 18047599.
- ↑ Manzi B, Loizzo AL, Giana G, Curatolo P (2008). "Autism and metabolic diseases". J Child Neurol. 23 (3): 307–14. doi:10.1177/0883073807308698. PMID 18079313.