Interaction between GSTT1 and GSTP1 allele variants as a risk modulating-factor for autism spectrum disorders

• We investigated the role of GSTP1, GSTT1, and GSTM1 polymorphisms in susceptibility to ASD.
• We identified a significant interaction between GSTP1 and GSTT1 in relation to ASD.
• Odds of ASD were higher in children with null GSTT1 and GSTP1 Ile105Val polymorphism.

We investigated the role of glutathione S-transferase (GST) genes in Autism Spectrum Disorder (ASD). We used data from 111 pairs of age- and sex-matched ASD cases and typically developing (TD) controls between 2 and 8 years of age from Jamaica to investigate the role of GST pi 1 (GSTP1), GST theta 1 (GSTT1), and GST mu 1 (GSTM1) polymorphisms in susceptibility to ASD. In univariable conditional logistic regression models we did not observe significant associations between ASD status and GSTT1, GSTM1, or GSTP1 genotype (all P > 0.15). However, in multivariable conditional logistic regression models, we identified a significant interaction between GSTP1 and GSTT1 in relation to ASD. Specifically, in children heterozygous for the GSTP1 Ile105Val polymorphism, the odds of ASD was significantly higher in those with the null GSTT1 genotype than those with the other genotypes [matched odds ratio (MOR) = 2.97, 95% CI (1.09, 8.01), P = 0.03]. Replication in other populations is warranted.