Associations among genotype, clinical phenotype, and intracellular localization of trafficking proteins in ARC syndrome

Holly Smith, Romain Galmes, Ekaterina Gogolina, Anna Straatman-Iwanowska, Kim Reay, Blerida Banushi, Christopher K. Bruce, Andrew R. Cullinane, Rene Romero, Richard Chang, Oanez Ackermann, Clarisse Baumann, Hakan Cangul, Fatma Cakmak Celik, Canan Aygun, Richard Coward, Carlo Dionisi-Vici, Barbara Sibbles, Carol Inward, Chong Ae KimJudith Klumperman, A. S. Knisely, Steven P. Watson, Paul Gissen

Research output: Contribution to journalArticlepeer-review

Abstract

Arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome is a rare autosomal recessive multisystem disorder caused by mutations in vacuolar protein sorting 33 homologue B (VPS33B) and VPS33B interacting protein, apical-basolateral polarity regulator (VIPAR). Cardinal features of ARC include congenital joint contractures, renal tubular dysfunction, cholestasis, severe failure to thrive, ichthyosis, and a defect in platelet alpha-granule biogenesis. Most patients with ARC do not survive past the first year of life. We report two patients presenting with a mild ARC phenotype, now 5.5 and 3.5 years old. Both patients were compound heterozygotes with the novel VPS33B donor splice-site mutation c.1225+5G>C in common. Immunoblotting and complementary DNA analysis suggest expression of a shorter VPS33B transcript, and cell-based assays show that c.1225+5G>C VPS33B mutant retains some ability to interact with VIPAR (and thus partial wild-type function). This study provides the first evidence of genotype-phenotype correlation in ARC and suggests that VPS33B c.1225+5G>C mutation predicts a mild ARC phenotype. We have established an interactive online database for ARC (https://grenada.lumc.nl/LOVD2/ARC) comprising all known variants in VPS33B and VIPAR. Also included in the database are 15 novel pathogenic variants in VPS33B and five in VIPAR.

Original languageEnglish
Pages (from-to)1656-1664
Number of pages9
JournalHuman Mutation
Volume33
Issue number12
DOIs
Publication statusPublished - Dec 2012

Keywords

  • Cholestasis
  • HOPS complex
  • Ostopenia
  • Recycling endosomes
  • VIPAR
  • VPS33B

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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