A case of hypomagnesemia with secondary hypocalcemia caused by Trpm6 gene mutation.

An offspring of marriage between two first cousins presented with atonic seizures developed on the 20(th) day of life. The physical examination of the case was normal. In laboratory results, Ca(+2) level was 5.7 mg/dl, Mg(+2): 0.4 mg/dl (1,3-2,1), PTH: 28.4 pg/ml (12-92), and P-: 4.5 mg/dl. The case was diagnosed as hypomagnesemia with secondary hypocalcemia (HSH) and TRPM6 gene mutation analysis revealed a homozygote mutation of E157X.