Exploring Potential Association between Autism Spectrum Disorder,Genetic Deletions in GSTT1, GSTP1, GSTM1, and Heavy MetalsFound in Hair Samples

Abstract

The aetiology of ASD is complex and likely involves a combination of genetic and environmental factors. The increasing prevalence of ASD has led to an increased interest in environmental factors and their potential influence. In this study, we investigated the association between genetic deletions of the GSTT1, GSTP1, and GSTM1 genes analyzed by Array-CHG and levels of heavy metals in hair samples of children with ASD analyzed by inductively coupled plasma optical emission spectrometry. We analyzed a total of 50 children (aged 2-8) of which 25 had been diagnosed with ASD and had genetic deletions in one or more of the analyzed genes (GSTT1, GSTP1, and GSTM1), and 25 control samples from children from the same geographic area exposed to the similar environmental conditions but with no deletions in these genes. We found that children with deletions in these genes had significantly elevated hair levels of aluminium (Al) in 100% of the examined children, and in some cases in combination with, mercury (Hg) – 1 case, lead (Pb) – 2 cases, cadmium (Cd) – 1 case, barium (Ba) - 8 cases, and nickel (Ni) – 2 cases. In the control group of children, 23 out of 25 had normal levels of heavy metals in their hair, while one child had a borderline value of aluminium (Al) and another had an increased level of thallium (Tl). Our findings suggest that genetic deletions in detoxification and antioxidant enzymes like GSTT1, GSTP1, and GSTM1 might be associated with increased levels of heavy metals thus leading to possible complex interactions between genetic and environmental factors, influencing the level of expression of symptoms and impairment in people with ASD.