Gain-of-function haplotype in the epithelial calcium channel TRPV6 is a risk factor for renal calcium stone formation

Suzuki, Yoshiro; Pasch, Andreas; Bonny, Olivier; Mohaupt, Markus G; Hediger, Matthias A; Frey, Felix J (2008). Gain-of-function haplotype in the epithelial calcium channel TRPV6 is a risk factor for renal calcium stone formation. Human molecular genetics, 17(11), pp. 1613-8. Oxford: Oxford University Press 10.1093/hmg/ddn048

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The rate-limiting step of dietary calcium absorption in the intestine requires the brush border calcium entry channel TRPV6. The TRPV6 gene was completely sequenced in 170 renal calcium stone patients. The frequency of an ancestral TRPV6 haplotype consisting of three non-synonymous polymorphisms (C157R, M378V, M681T) was significantly higher (P = 0.039) in calcium stone formers (8.4%; derived = 502, ancestral = 46) compared to non-stone-forming individuals (5.4%; derived = 645, ancestral = 37). Mineral metabolism was investigated on four different calcium regimens: (i) free-choice diet, (ii) low calcium diet, (iii) fasting and (iv) after a 1 g oral calcium load. When patients homozygous for the derived haplotype were compared with heterozygous patients, no differences were found with respect to the plasma concentrations of 1,25-vitamin D, PTH and calcium, and the urinary excretion of calcium. In one stone-forming patient, the ancestral haplotype was found to be homozygous. This patient had absorptive hypercalciuria. We therefore expressed the ancestral protein (157R+378V+681T) in Xenopus oocytes and found a significantly enhanced calcium permeability when tested by a (45)Ca(2+) uptake assay (7.11 +/- 1.93 versus 3.61 +/- 1.01 pmol/min/oocyte for ancestral versus derived haplotype, P < 0.01). These results suggest that the ancestral gain-of-function haplotype in TRPV6 plays a role in calcium stone formation in certain forms of absorptive hypercalciuria.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Dermatology, Urology, Rheumatology, Nephrology, Osteoporosis (DURN) > Clinic of Nephrology and Hypertension
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Biochemistry and Molecular Medicine

UniBE Contributor:

Pasch, Andreas; Mohaupt, Markus; Hediger, Matthias and Frey, Felix Julius

ISSN:

0964-6906

ISBN:

18276610

Publisher:

Oxford University Press

Language:

English

Submitter:

Markus Georg Mohaupt

Date Deposited:

04 Oct 2013 15:03

Last Modified:

27 Apr 2018 08:46

Publisher DOI:

10.1093/hmg/ddn048

PubMed ID:

18276610

Web of Science ID:

000256170800010

BORIS DOI:

10.7892/boris.27336

URI:

https://boris.unibe.ch/id/eprint/27336 (FactScience: 106077)

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