Author: Amanda Randunne
Over the years, many researchers have looked into the cause of autism spectrum disorders (ASD) in humans. ASD is thought to emerge because of genetic as well as environmental factors. A study, FADS1-FADS2 and ELOVL2 gene polymorphisms in susceptibility to autism spectrum disorders in Chinese Children came out recently that investigates how specific genes can play a role in the diagnosis of ASD. Genomic analyses have found that single nucleotide polymorphisms (SNPs) that are present in specific genes have been correlated to the predisposition to ASD in children and can explain a difference in phenotype that is present.
243 patients with ASD were recruited from the Child Development and Behavior Research Center of Harbin Medical University, while in another group, there were 243 non-ASD patients selected from kindergartens in Harbin, China. All the subjects in both the control and experimental group were from Chinese Han ethnicity. A clinical assessment was performed to assess autism symptoms in three domains, such as social, communication, and repetitive behavior, as well as IQ scores were determined. Genotype data was collected to identify SNPs present in FADS1, FADS2, and ELOVL2 genes. The FADS1 and FADS2 genes are next to each other in a cluster on chromosome 11 and can be found in human tissues, such as liver, heart, and brain. Possible relationships between genotypic and phenotypic characteristics were measured through an analysis of language level, IQ, sex, and age at assessment.
The results showed that 5 SNPs (rs526126, rs17606561, rs3756963, rs10498676, rs9468304) were selected for in the analyses of the relationships between gene polymorphisms and with ASD-specific features, such as ADI-R and ADOS domains. The genetic variant present in FADS2 (rs526126) can reduce desaturase activity, functionality, or expression and can result in a lower concentration of LC-PUFAs, which can lead to other downstream consequences. The current study showed that the allele distributions of tag SNPs in ELOVL2 gene was not different significantly between ASD cases and controls; however, four of the SNPs were specifically related to ASD risk in an overdominate/recessive model. There was some limitations in that the study in that there was not enough diversity in the sample and that there was a small sample size.