Mutations in hexaminidase A, hexaminidase B, Niemann-Pick type C2, and ATP-binding cassette transporter A1 (ABCA1) cause Tay-Sachs [50], Sandhoff disease [51], Niemann-Pick type C2 (NPC2) [52], and Tangier disease [53], respectively. Here, ABCA1 is linked to Sandhoff disease.