GSTM1 and cataract: In addition, at least 10 gene mutations can indirectly lead to cataracts, including genes that function in antioxidant metabolism (GSTM1, GSTT1), xenobiotic detoxification (NAT2), DNA repair (ERCC2), folate metabolism (MTHFR), lactose metabolism (LCT), RNA demethylation (FTO), lipid/cholesterol transport (APOE4), kinesin/microtubule motor transport (KLC1), and one of unknown function (ARCC1).[16] The patient in case 1 had a hypermature cataract at a relatively young age, which is an atypical type of cataract.