Molecular investigations to improve diagnostic accuracy in patients with ARC syndrome.
Arthrogryposis, Renal dysfunction and Cholestasis (ARC) syndrome is a multi-system autosomal recessive disorder caused by germline mutations in VPS33B. The detection of germline VPS33B mutations removes the need for diagnostic organ biopsies (these carry a>50% risk of life-threatening haemorrhage due to platelet dysfunction); however, VPS33B mutations are not detectable in approximately 25% of patients. In order further to define the molecular basis of ARC we performed mutation analysis and mRNA and protein studies in patients with a clinical diagnosis of ARC. Here we report novel mutations in VPS33B in patients from Eastern Europe and South East Asia. One of the mutations was present in 7 unrelated Korean patients. Reduced expression of VPS33B and cellular phenotype was detected in fibroblasts from patients clinically diagnosed with ARC with and without known VPS33B mutations. One mutation-negative patient was found to have normal mRNA and protein levels. This patient's clinical condition improved and he is alive at the age of 2.5 years. Thus we show that all patients with a classical clinical course of ARC had decreased expression of VPS33B whereas normal VPS33B expression was associated with good prognosis despite initial diagnosis of ARC.
Cullinane
Andrew R
AR
Department of Medical and Molecular Genetics, University of Birmingham, Birmingham, UK.
Straatman-Iwanowska
Anna
A
Seo
Jeong K
JK
Ko
Jae S
JS
Song
Kyung S
KS
Gizewska
Maria
M
Gruszfeld
Dariusz
D
Gliwicz
Dorota
D
Tuysuz
Beyhan
B
Erdemir
Gulin
G
Sougrat
Rachid
R
Wakabayashi
Yoshiyuki
Y
Hinds
Rupert
R
Barnicoat
Angela
A
Mandel
Hanna
H
Chitayat
David
D
Fischler
Björn
B
Garcia-Cazorla
Angels
A
Knisely
A S
AS
Kelly
Deirdre A
DA
Maher
Eamonn R
ER
Gissen
Paul
P
D001176:Arthrogryposis / Q000150:complications* / Q000175:diagnosis* / Q000208:ethnology; D002675:Child, Preschool; D002779:Cholestasis / Q000150:complications* / Q000175:diagnosis* / Q000208:ethnology; D005347:Fibroblasts / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D007223:Infant; D007674:Kidney Diseases / Q000150:complications* / Q000175:diagnosis* / Q000208:ethnology; D008297:Male; D009154:Mutation / Q000235:genetics; D013577:Syndrome; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism
C411584:VPS33B protein, human; D033921:Vesicular Transport Proteins