NPC1 and Cerebellar atrophy: Whole-exome sequencing analysis identified the sorting nexin 14 (SNX14) gene as a candidate gene locus for SCAR20 onset, and SNX14 loss-of-function mutations account for approximately 9.9% of early-onset cerebellar atrophy and ataxia cases, which represents a higher percentage than any other potential genes related to cerebellar atrophy, such as GRID2 (2.47%), NPC1 (1.23%) and SETX (1.23%) [7].