VPS33B gene is a member of the Sec-1 domain family and encodes vacuolar protein sorting-associated protein 33B. VPS33B protein, a homolog of yeast class C Vps33 protein, is considered to be involved in vesicle-mediated protein trafficking, membrane fusion of late endosomes/lysosomes, endosomal maturation, and the apical recycling pathway.
Mutations in VPS33B gene result in abnormal intracellular protein trafficking and cause arthrogryposis-renal dysfunction-cholestasis 1.