NPC2 mutations cause a cholesterol and sphingolipid storage disorder known as Niemann-Pick disease type C (NPC), which has severe implications for cognitive, liver, and spleen function (Ribeiro et al., 2001; Park et al., 2003; Vanier and Millat, 2003; Pentchev, 2004; Chang et al., 2005; Evans and Hendriksz, 2017). This evidence concerns the gene NPC2 and Niemann-Pick disease type C.