The involvement of serotonin polymorphisms in autistic spectrum symptomatology.

BACKGROUND:Autism spectrum disorders (ASD) are highly inherited developmental syndromes, resulting from a complex interaction between environmental and genetic factors. To date, only a limited number of genetic variants have been discovered with respect to autism, and their contribution to the development of the disorder has not been clearly determined. Investigation of specific autistic symptomatology may improve the chances of identifying related genes and may help to better understand these disorders. MATERIALS AND METHODS:We investigated the contribution of 80 genetic variants in 15 serotonin genes to ASD phenotypes [intelligence quotation (IQ), intellectual disability (ID) and language onset delay (LD)] in a cohort of 141 children and young adults (121 male patients and 20 female patients, average age 14.5±5.1 years). RESULTS:Two polymorphisms in the HTR2B gene, rs10194776 and rs16827801, were associated with IQ (P=0.0004 and 0.003, respectively), ID (P=0.02 and 0.03) and LD (P=0.04 and 0.004). Nominal associations were also detected between the ASD phenotypes investigated and 5-HT2A, 5-HT4 and 5-HT6 genetic variants. CONCLUSION:Our study provides evidence of the contribution of serotonergic variants to IQ, ID and LD in ASD patients.