Rapid communication Two novel mutations of the gene for Kir 1.1 (ROMK) in neonatal Bartter syndrome

Bartter syndrome, an autosomal recessive renal tubular disorder, is associated with hypokalemic metabolic alkalosis with high renin and aldosterone plasma con- centrations with low or normal blood pressure and renal salt loss. Two genes, the gene encoding the furosemide-sensi- tive apical Na-K-2Cl cotransporter (NKCC2) and the gene encoding the luminal inwardly-rectifying potassium chan- nel Kir 1.1 (ROMK), have been reported to cause the neo- natal subtype of Bartter syndrome. In a patient with neo- natal Bartter syndrome, we report two novel mutations resulting in amino acid exchanges Ala156Val and Leu220Phe in the gene for Kir 1.1 that have been identified by single-strand conformation polymorphism analysis and subsequent direct sequencing. Both mutations occur in functional relevant domains of the channel protein and are therefore highly suggestive of altering channel properties.