Large deletion of the 5' end of the ROMK1 gene causes antenatal Bartter syndrome.

Mutations in exon 5 of the ROMK1 gene (KCNJ1) have recently been observed in antenatal Bartter syndrome patients. This study describes a homozygous deletion removing KCNJ1 exons 1 and 2 observed in a consanguineous family with antenatal Bartter syndrome. Absence of the untranslated exon 1 led to the deletion of transcription elements located in this exon that may cause the disease. Deletion of exon 1 transcription elements should lead to the absence of hROMK2-K5 transcripts, whereas hROMK1 transcripts should normally be transcripted. Consequently, probably only hROMK2-K5 transcripts are expressed in the medullary thick ascending limb of Henle.