Clinical and experimental nephrology
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Clin. Exp. Nephrol. · Aug 2009
Case ReportsFamilial hypomagnesemia with hypercalciuria and nephrocalcinosis: unusual clinical associations and novel claudin16 mutation in an Egyptian family.
Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is a rare autosomal recessive tubular disorder that eventually progresses to renal failure, depending upon the extent of nephrocalcinosis. Its basic pathogenesis is impaired tubular resorption of magnesium and calcium in the thick ascending limb of the loop of Henle (TAL) due to a genetic defect in paracellin-1 (a tight junction protein expressed in TAL). Mutations of the claudin16 gene (CLDN16), formerly called paracellin-1 gene (PCLN-1), have been linked to FHHNC. ⋯ The above-mentioned clinical data in the two affected sibs together with the family history of end-stage renal disease associated with nephrocalcinosis and high myopia suggested a diagnosis of FHHNC, which was confirmed for the first time in an Egyptian family by a novel mutation in exon 1 of the CLDN16 gene. Genitourinary associations with FHHNC have not yet been reported in the literature. Here, we will try to highlight the principles of mutation detection based on sequencing with the use of the online NCBI databases, statistics and other search tools.