GBA1 and Parkinson disease: Variants in genes such as SNCA (synuclein alpha, encoding α-Syn), GBA (glucosylceramidase beta, encoding GBA protein), LRRK2 (leucine-rich repeat kinase 2, encoding LRRK2 protein), and MAPT (microtubule associated protein, encoding Tau) have been found to increase the risk of PD (Bras and Singleton 2009).