ATXN7 and major depressive disorder: Apart from retinal degeneration and progressive loss of motor control caused by pathogenic expansion of the ATXN7 polyglutamine tract, there have also been reports of various psychiatric and metabolic traits that are correlated with ‘normal range’ CAG repeat size polymorphisms in ATXN7. Specifically, alleles with relatively larger CAG repeats within the normal range have been associated with increased lifetime risk of depression and increased body mass index (BMI) in population-based cohort studies (Arrasate et al., 2004; Lajoie and Snapp, 2013).