GLUD2 and Parkinson disease: From sequencing GDH1 and GDH2 genes in Parkinson’s disease patients, an A445S mutation in GDH2 that increased enzyme activity was found to be correlated with 6–13 year earlier onset of symptoms (excessive ammonia toxicity on pyramidal neurons), but not in females likely due to the strong estrogen inhibition of the mutant GDH2.