Eating Disorders and Parkinson's Disease-2: Genetic Epidemiology and Shared Genomics.

ObjectiveIndividuals with anorexia nervosa (AN) share premorbid traits with Parkinson's Disease (PD) (e.g., anxiety) and exhibit a two-fold relative risk of a reported family history of PD. Published estimates of intra- and inter-disorder genetic architecture were extracted and compared prior to conducting novel analyses to provide evidence for cross-disorder genetic risk.MethodsNational register or meta-analytic familial, twin, and common variant genome-wide studies were searched; estimates and findings were extracted and compared. Novel cross-disorder conditional and conjunctional false discovery rate analyses were performed.ResultsSibling relative risks and additive genetic estimates of the two disorders were similar. AN had greater common variant heritability than PD whether measured via infinitesimal model (linkage disequilibrium score regression, LDSC) or causal mixture model (MiXeR). AN had greater polygenicity than PD (mean (SD) 2.50E-03 (1.64E-04) versus 2.72E-4 (1.47E-05), p