Environmental and Genetic effects on Autism ( Medical Laboratory Sciences )

Supervisor:

Dr. Amjad Hussien

Abstract :

Autism spectrum disorder (ASD) is one of the fastest-growing developmental disorders, and boys are nearly five times more likely to have the disorder than girls, however affected girls do have a more sever pattern. Autism involves a deficit in social Communication, Cognitive defects, Restrictive/Repetitive behaviors. Autism is a disorder in the development of brain, though other important factors may help to the occurrence of the disorder from environmental factors to Genetics.

Indirect evidence for an environmental contribution to autism comes from studies demonstrating the sensitivity of the developing brain to external exposures such as lead, ethyl alcohol and methyl mercury. But the most powerful proof-of-concept evidence derives from studies specifically linking autism to exposures in early pregnancy – thalidomide, misoprostol, and valproic acid; maternal rubella infection; and the organophosphate insecticide, chlorpyrifos. The high degree of heritability of ASD suggests that environmental influences are likely to operate through their interaction with genetic susceptibility during vulnerable periods of development. The studies about the contribution of genetic and autism is a still going studies, the identification weather it’s a genetic disorder or not is still questionable because autistic patient do not have autistic parents , and only 2% of autistic patients have autistic siblings.

In this work, literature were reviewed on the etiological substrates of ASD and explores how genetic epidemiology approaches including gene-environment interactions can play a role in identifying factors associated with ASD etiology. New genetic and bioinformatics strategies have yielded important clues to ASD genetic substrates. The next steps for understanding ASD pathogenesis require significant effort to focus on how genes and environment interact with one another in typical development and its perturbations. Clearly, countless fetuses and babies are exposed to “environmental risk factors” such as these without ever developing autism. But if a child is genetically predisposed to autism, it appears that these influences further increase the risk. For this reason, we say that environmental factors increase the risk of autism rather than cause it.