Age of onset (AO) is associated with greater self-reported genetic risk for major depression (MD) in cases, yet not associated with common variant polygenic risk for MD, a recent study found. Researchers estimated the SNP-based heritability of AO in a case-control sample (n=9,854; MD case, n=4,927). Common single nucleotide polymorphism heritability of MD was also examined across both high and low median-split AO groups, and best linear unbiased predictor (BLUP) scores of polygenic risk, in split-halves, were used to predict AO. Distributions of genetic risk across early and late AO were compared, and presence of self-reported family history of MD was also examined as a predictor of AO. Researchers found:
- AO was not significantly heritable and polygenic risk derived from the aggregated effects of common genetic variants did not significantly predict AO in any analysis.
- AO was modestly but significantly lower in cases with a first-degree genetic family history of MD.
Docherty AR, Edwards AC, Yang F, et al. Age of onset and family history as indicators of polygenic risk for major depression. [Published ahead of print February 2, 2017]. Depress Anxiety. doi:10.1002/da.22607.