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Nephrol Dial Transplant. 2015 Apr;30(4):636-44. doi: 10.1093/ndt/gfu374. Epub 2014 Dec 3.

Retrospective cohort study of familial hypomagnesaemia with hypercalciuria and nephrocalcinosis due to CLDN16 mutations.

Author information

1
Department of Pediatric Nephrology, Medical University of Lublin, Poland.
2
Children's Hospital, Poznań, Poland.
3
Department of General Pediatrics, Pediatric Nephrology, University Children's Hospital, Münster, Germany.
4
Center of Pediatrics and Oncology, Chorzów, Poland.
5
Department of Pediatrics in Zabrze, Medical University of Silesia, Katowice, Poland.
6
Department of Pediatric Nephrology, Jagiellonian University Medical College, Kraków, Poland.
7
Nephrology Division, Department of Pediatrics and Immunology, Polish Mothers Memorial Hospital Research Institute, Lódź, Poland.
8
Department of Pediatric Cardiology and Nephrology, University of Medical Sciences, Poznań, Poland.

Abstract

BACKGROUND:

Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC) is a rare autosomal recessive tubular disorder exhibiting a high risk for progressive chronic kidney disease (CKD).

METHODS:

This is a retrospective multicentre study of 25 paediatric cases with FHHNC in Poland. Median age at diagnosis was 4 years and median follow-up time was 4.8 years.

RESULTS:

All cases of FHHNC carried recessive mutations in CLDN16. The founder mutation in CLDN16, Leu151Phe, was the most frequent cause of FHHNC in Polish patients, with 13 (52%) cases being homozygous and 5 (20%) carrying Leu151Phe allele in compound heterozygosity. All cases showed nephrocalcinosis, increased urinary fractional excretion of magnesium and hypercalciuria. Other disease features included hypomagnesaemia (76%), hyperparathyroidism (76%), hyperuricaemia (56%) and hypocitraturia (60%). Treatment with thiazides effectively reduced hypercalciuria in most cases. During follow-up, renal function declined in 60% of patients; 12% of patients reached CKD stage 3 or 4 and one patient developed end-stage renal failure.

CONCLUSIONS:

We report one of the largest cohorts of FHHNC cases caused by CLDN16 mutations. A missense variant of CLDN16, Leu151Phe, is the most common mutation responsible for FHHNC in Poland. Additionally, we found that normomagnesaemia does not exclude FHHNC and the calculation of fractional excretion of Mg can be diagnostic in the setting of normomagnesaemia. We also demonstrate the efficacy of a treatment with thiazides in terms of hypercalciuria in the majority of patients.

KEYWORDS:

CLDN16; FHHNC; hypercalciuria; hypomagnesaemia; nephrocalcinosis

PMID:
25477417
DOI:
10.1093/ndt/gfu374
[Indexed for MEDLINE]

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