GBA1 encodes glucocerebrosidase (GCase), a lysosomal enzyme that catalyzes hydrolysis of glucosylceramides into ceramides and glucose, playing a central role in complex lipid degradation and cellular membrane turnover 123. Beyond hydrolysis, GBA1 participates in transglucosylation reactions transferring glucose from glucosylceramide to cholesterol 24, and can metabolize galactosylceramides and plant glycosyl phytosterols with lower efficiency 35. Through ceramide production, GBA1 contributes to PKC-activated salvage pathways 6. Biallelic GBA1 mutations cause Gaucher disease, an autosomal recessive lysosomal storage disorder characterized by glucosylceramide accumulation in macrophages, affecting ~1/40,000-60,000 births, with three neurological severity types 78. Monoallelic GBA1 variants represent the most common genetic risk factor for Parkinson's disease, with reduced GCase activity impairing sphingolipid metabolism, lysosomal autophagy, and mitochondrial function 91011. GBA1 mutations also associate with dementia with Lewy bodies and impaired α-synuclein clearance 1211. Gene therapy delivering functional GBA1 to the brain shows promise in preclinical studies and clinical trials for GBA1-associated Parkinson's disease 1013.