GSTM1 and autism: Polymorphisms in glutathione S-transferase mu 1 (GSTM1), glutathione S-transferase pi 1 (GSTP1), and glutathione peroxidase 1 (GPX1), which modulate the response to oxidative stress, have been associated with increased autism risk (Buyske et al. 2006; Ming et al. 2009; Williams et al. 2007).