GSTM5 and Abnormal retinal morphology: Of note, a reduced transcript level of GSTM5 and GSTT1 in human retinae and retinal pigment epithelium (RPE) owing to promoter hypermethylation have been associated with an increased risk to develop age-related macular degeneration - a retinal disease associated with oxidative stress induced RPE and neuronal degeneration (75).