Please check our recent paper published in Translational Psychiatry in which we showed that DNA repeat polymorphisms in two particular genes, i.e. ATXN7 and TBP, were associated with the risk of lifetime depression in two large and well-characterized Dutch cohorts — the Netherlands Study of Depression and Anxiety (NESDA) and the Netherlands Study of Depression in Older Persons (NESDO) —including 2165 depressed and 1058 non-depressed individuals. We found that carriers of either ATXN7 or TBP alleles with relatively large CAG repeat sizes in both alleles had a substantially increased risk of lifetime depression. I believe that these as well as many other DNA repeat polymophisms could actually account for a substanial degree of ‘missing heritability’, and not only of depression. The paper is open access, so please feel free to disseminate!
Gardiner SL, Van Belzen MJ, Boogaard MW; Van Roon-Mom WM, Rozing MP, Van Hemert AM, Smit JH, Beekman AT, Van Grootheest G, Schoevers RA, Oude Voshaar RC, Comijs HC, Penninx BW, Van der Mast RC, Roos RA, Aziz NA (2017). Large normal-range TBP and ATXN7 CAG repeat lengths are associated with increased lifetime risk of depression. Translational Psychiatry. 7(6): e1143. doi: 10.1038/tp.2017.116.