VPS33B mutation with ichthyosis, cholestasis, and renal dysfunction but without arthrogryposis:: Incomplete arc syndrome phenotype

Arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome is a rare multisystem disorder first described in 1979(1) and recently ascribed to mutation in VPS33B, whose product acts in intracellular trafficking.(2) Arthrogryposis, spillage of various substances in the urine, and conjugated hyperbilirubinemia define an ARC core phenotype, in some patients associated with ichthyosis, central nervous system malformation, deafness, and platelet abnormalities. We describe a patient with cholestasis, ammoaciduria, ichthyosis, partial callosal agenesis, and sensorineural deafness who, although homozygous for the novel VPS33B mutation 971delA/K324fs, predicted to abolish VPS33B function, did not exhibit arthrogryposis. The phenotypes associated with VPS33B mutation may include incomplete ARC.