The Vacuolar H+-ATPase B1 Subunit Polymorphism p.E161K Associates with Impaired Urinary Acidification in Recurrent Stone Formers

Dhayat, Nasser; Schaller, André; Albano, Giuseppe; Poindexter, John; Griffith, Carolyn; Pasch, Andreas; Gallati, Sabina; Vogt, Bruno; Moe, Orson; Fuster, Daniel Guido (2015). The Vacuolar H+-ATPase B1 Subunit Polymorphism p.E161K Associates with Impaired Urinary Acidification in Recurrent Stone Formers. Journal of the American Society of Nephrology, 27(5), pp. 1544-1554. Lippincott Williams & Wilkins 10.1681/ASN.2015040367

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Mutations in the vacuolar–type H+-ATPase B1 subunit gene ATP6V1B1 cause autosomal–recessive distal renal tubular acidosis (dRTA). We previously identified a single-nucleotide polymorphism (SNP) in the human B1 subunit (c.481G.A; p.E161K) that causes greatly diminished pump function in vitro. To investigate the effect of this SNP on urinary acidification, we conducted a genotype-phenotype analysis of recurrent stone formers in theDallas and Bern kidney stone registries. Of 555 patients examined, 32 (5.8%) were heterozygous for the p.E161K SNP, and the remaining 523 (94.2%) carried two wild–type alleles. After adjustment for sex, age, body mass index, and dietary acid and alkali intake, p.E161K SNP carriers had a nonsignificant tendency to higher urinary pH on a random diet (6.31 versus 6.09; P=0.09). Under an instructed low–Ca and low–Na diet, urinary pH was higher in p.E161K SNP carriers (6.56 versus 6.01; P,0.01). Kidney stones of p.E161K carriers were more likely to contain calcium phosphate than stones of wild-type patients. In acute NH4Cl loading, p.E161K carriers displayed a higher trough urinary pH (5.34 versus 4.89; P=0.01) than wild-type patients. Overall, 14.6% of wild-type patients and 52.4% of p.E161K carriers were unable to acidify their urine below pH 5.3 and thus, can be considered to have incomplete dRTA. In summary, our data indicate that recurrent stone formers with the vacuolar H+-ATPase B1 subunit p.E161K SNP exhibit a urinary acidification deficit with an increased prevalence of calcium phosphate– containing kidney stones. The burden of E161K heterozygosity may be a forme fruste of dRTA.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > Unit Childrens Hospital > Forschungsgruppe Humangenetik
04 Faculty of Medicine > Department of Gynaecology, Paediatrics and Endocrinology (DFKE) > Clinic of Paediatric Medicine
04 Faculty of Medicine > Other Institutions > Teaching Staff, Faculty of Medicine
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Biochemistry and Molecular Medicine
04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > Unit Childrens Hospital > Forschungsgruppe Nephrologie / Hypertonie
04 Faculty of Medicine > Department of Dermatology, Urology, Rheumatology, Nephrology, Osteoporosis (DURN) > Clinic of Nephrology and Hypertension

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Dhayat, Nasser; Schaller, André; Albano, Giuseppe; Pasch, Andreas; Gallati, Sabina; Vogt, Bruno and Fuster, Daniel Guido

Subjects:

600 Technology > 610 Medicine & health
500 Science > 570 Life sciences; biology

ISSN:

1046-6673

Publisher:

Lippincott Williams & Wilkins

Language:

English

Submitter:

Daniel Guido Fuster

Date Deposited:

20 Jan 2016 07:26

Last Modified:

09 Sep 2017 20:25

Publisher DOI:

10.1681/ASN.2015040367

PubMed ID:

26453614

BORIS DOI:

10.7892/boris.75272

URI:

https://boris.unibe.ch/id/eprint/75272

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