Associations of Metabolic Genes (GSTT1, GSTP1, GSTM1) and Blood Mercury Concentrations Differ in Jamaican Children with and without Autism Spectrum Disorder

Abstract

We investigated interactive roles of three metabolic glutathione S-transferase (GST) genes (<i>GSTP1</i>, <i>GSTT1</i>, and <i>GSTM1</i>) and autism spectrum disorder (ASD) status in relation to blood Hg concentrations (BHC) of Jamaican children. We used data from 266 children (2-8 years) with ASD and their 1:1 age- and sex-matched typically developing (TD) controls. After adjusting General Linear Models for child's age, socioeconomic status, consumption of leafy vegetables, fried plantain, canned fish, and the interaction between <i>GSTP1</i> and <i>GSTT1</i>, we found significant interactions between <i>GSTP1</i> and ASD status in relation to BHC either in a co-dominant or dominant genetic model for <i>GSTP1</i>(<i>P</i> < 0.001, <i>P</i> = 0.007, respectively). In the co-dominant model for the Ile105Val <i>GSTP1</i> polymorphism, geometric mean (GM) BHC in ASD cases with genotype Ile/Ile were significantly higher than in cases with the Ile/Val genotype (0.73 vs. 0.48 µg/L, <i>P</i> = 0.01). In contrast, in TD controls with the Ile/Val genotype GM BHC were significantly higher than in those with the Ile/Ile genotype (0.72 vs. 0.49 µg/L, <i>P</i> = 0.03) or the Val/Val genotype (0.72 vs. 0.51 µg/L, <i>P</i> = 0.04). Although our findings are consistent with the role of <i>GSTP1</i> in detoxification of Hg, replication in other populations is warranted.