Gitelman Syndrome in a School Boy Who Presented with Generalized Convulsion and Had a R642HR642W Mutation in the SLC12A3 Gene

Abstract EN

An 8-year-old Japanese boy presented with a generalized convulsion.

He had hypokalemia (serum K 2.4 mEq/L), hypomagnesemia, and metabolic alkalosis (BE 5.7 mmol/L).

In addition, his plasma renin activity was elevated.

He was tentatively diagnosed with epilepsy on the basis of the electroencephalogram findings and was treated by potassium L-aspartate and carbamazepine to control the hypokalemia and seizure, respectively.

However, a year later, the patient continued to have similar abnormal laboratory data.

A presumptive diagnosis of Gitelman syndrome (GS) was then made and the patient’s peripheral blood mononuclear cells were subjected to sequence analysis of the SLC12A3 gene, which encodes a thiazide-sensitive sodium-chloride cotransporter.

The patient was found to have compound heterozygous mutations, namely, R642H inherited from his father and R642W inherited from his mother.

Thus, if a patient shows persistent hypokalemia and metabolic alkalosis, GS must be considered, even if the patient exhibits atypical clinical symptoms.