Lysosomal storage diseases are caused by genetic mutations that result in an inborn error of metabolism that affects the way the cells dispose of metabolic waste. Specifically, Pompe disease is caused by a deficiency in the enzyme, α-1,4-glucosidase. Patients with Tay-Sachs lack the enzyme, hexosaminidase A, which causes a gradual toxic accumulation of the lipid GM2 ganglioside in the cell. Gaucher disease is a deficiency of β-glucocerebrosidase (GBA), which leads to a toxic buildup of glucocerebroside in the organs and bone marrow. Unlike the others, neither Kabuki syndrome nor Parkinson disease are lysosomal storage diseases. Kabuki syndrome is a genetic disease in which the mutated gene alters gene expression regulation. Parkinson disease is a neurodegenerative disease.