title: Hypomagnesemia and nephrocalcinosis in a patient with two heterozygous mutations in the CLDN16 gene.
abstract: 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.
authors.affiliation: Section of Nephrology and Hypertension, Division of Endocrinology, Department of Internal Medicine, Eberhard-Karls-University Tübingen, Tübingen - Germany. harald.staiger@med.uni-tuebingen.de
authors.forename: Katrin
authors.initials: K
authors.lastname: Staiger
authors.forename: Harald
authors.initials: H
authors.lastname: Staiger
authors.forename: Carina
authors.initials: C
authors.lastname: Haas
authors.forename: Claus
authors.initials: C
authors.lastname: Thamer
authors.forename: Teut
authors.initials: T
authors.lastname: Risler
authors.forename: Fausto
authors.initials: F
authors.lastname: Machicao
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Häring
mesh_terms: 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*
chemical_list: D057167:Claudins; D008565:Membrane Proteins; C502010:claudin 16; D008274:Magnesium