Kidney Transplantation From a Heterozygous CLDN19 Carrier in a Child With FHHNC: A 2-Year Follow-Up.

Authors

Hakan Erdoğan, Mahmut Esat Danışoğlu, Hüseyin Çelik, Murat Şamlı, Bülent Oktay

Published in

Pediatric transplantation. Volume 30. Issue 10. Pages e70495.

Abstract

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is a rare autosomal recessive tubulopathy caused by mutations in CLDN16 or CLDN19, leading to progressive chronic kidney disease. While kidney transplantation is the definitive treatment, the safety of using living-related heterozygous carrier donors remains debated due to potential subclinical tubular dysfunction. We report the 2-year follow-up of a pediatric patient with FHHNC and a CLDN19 mutation who received a graft from his heterozygous carrier mother.
A male patient presented at 3 months of age with nephrocalcinosis, hypercalciuria, and hypomagnesemia. Genetic analysis confirmed a homozygous CLDN19 (G179S) mutation. Consistent with the CLDN19 phenotype, the patient exhibited severe ocular involvement, including high myopia and macular coloboma. He progressed to end-stage kidney disease by age 15 and underwent living-related kidney transplantation from his mother (a heterozygous carrier) at age 16. Pre-operative donor evaluation showed normal renal function without proteinuria, hypercalciuria, nephrolithiasis, or nephrocalcinosis.
At 24 months post-transplantation, graft function remained stable with a serum creatinine of 1.22 mg/dL and a 24-h creatinine clearance of 94 mL/min/1.73 m². Metabolic abnormalities were fully corrected; serum magnesium stabilized at 1.89 mg/dL without supplementation, the urinary calcium/creatinine ratio normalized (2.6 to 0.06), and proteinuria decreased from 2580 mg/day to 324 mg/day. The heterozygous donor maintained stable renal function (24-h creatinine clearance 86 mL/min/1.73 m²) without proteinuria, nephrolithiasis, or metabolic complications during follow-up.
Given the shortage of deceased donor organs, heterozygous parents may be considered suitable donors for children with FHHNC, provided they undergo comprehensive genetic, biochemical, and radiological evaluation to exclude evidence of tubular dysfunction. However, this conclusion should be limited to carefully selected donors, and longer-term follow-up is required to establish the safety of kidney donation in heterozygous CLDN19 carriers.

PMID:
42855920
Bibliographic data and abstract were imported from PubMed on 10 Oct 2026.

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