Hypomagnesemia and nephrocalcinosis in a patient with two heterozygous mutations in the CLDN16 gene.
We report the case of a 20-year-old male Caucasian patient with diagnosed nephrocalcinosis and a medical history of seizures and recurrent urinary tract infections. Laboratory investigations revealed clinical and biochemical abnormalities characteristic of familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC). Since FHHNC is caused by mutations in the CLDN16 gene encoding a renal tight junction protein, we sequenced the complete coding region of this gene and detected two heterozygous mutations, the known Leu151Phe (+453G-->T) mutation and a novel Cys120Arg (+358T-->C) mutation. Due to their location within the primary structure of Claudin-16, both mutations are suggested to interfere with renal paracellular magnesium conductance.
Staiger
Katrin
K
Section of Nephrology and Hypertension, Division of Endocrinology, Department of Internal Medicine, Eberhard-Karls-University Tübingen, Tübingen - Germany. harald.staiger@med.uni-tuebingen.de
Staiger
Harald
H
Haas
Carina
C
Thamer
Claus
C
Risler
Teut
T
Machicao
Fausto
F
Häring
Hans-Ulrich
HU
D000328:Adult; D057167:Claudins; D005091:Exons / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D053565:Hypercalciuria / Q000235:genetics / Q000652:urine; D008274:Magnesium / Q000097:blood*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology; D009154:Mutation / Q000235:genetics*; D009397:Nephrocalcinosis / Q000097:blood / Q000235:genetics*
D057167:Claudins; D008565:Membrane Proteins; C502010:claudin 16; D008274:Magnesium