Genetic heterogeneity in familial renal magnesium wasting.

Isolated hereditary renal magnesium (Mg) wasting may result from mutations in the renal tubular epithelial cell tight junction protein paracellin-1 gene or the tubular Na(+),K(+)-ATPase gamma-subunit gene FXYD2. The FXYD2 gene mutation was discovered in two Dutch families as an autosomal dominant disorder. It is characterized by isolated renal Mg wasting with resultant symptomatic hypomagnesemia.