title: Expanding the spectrum of genetic mutations in antenatal Bartter syndrome type II.
abstract: Bartter syndrome (BS) is a group of genetic disorders characterized by hypokalemic metabolic alkalosis, hyponatremia and elevated renin and aldosterone plasma concentrations. BS type II is caused by mutations in the KCNJ1 gene and usually presents with transient hyperkalemia. We report here a novel KCNJ1 mutation in a male neonate, prematurely born after a pregnancy complicated by polyhydramnios. The infant presented with typical clinical and laboratory findings of BS type II, such as hyponatremia, hypochloremic metabolic alkalosis, severe weight loss, elevated renin and aldosterone levels and transient hyperkalemia in the early postnatal period, which were later normalized. Molecular analysis revealed a compound heterozygous mutation in the KCNJ1 gene, consisting of a novel K76E and an already described V315G mutation, both affecting functional domains of the channel protein. Typical manifestations of antenatal BS in combination with hyperkalemia should prompt the clinician to search for mutations in the KCNJ1 gene first.
authors.affiliation: Third Department of Pediatrics, Medical School, University General Hospital Attikon, University of Athens, Athens, Greece. afretz@med.uoa.gr
authors.forename: Andreas
authors.initials: A
authors.lastname: Fretzayas
authors.forename: Evangelia
authors.initials: E
authors.lastname: Gole
authors.forename: Achilleas
authors.initials: A
authors.lastname: Attilakos
authors.forename: Anna
authors.initials: A
authors.lastname: Daskalaki
authors.forename: Polyxeni
authors.initials: P
authors.lastname: Nicolaidou
authors.forename: Anna
authors.initials: A
authors.lastname: Papadopoulou
mesh_terms: D000471:Alkalosis / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D000483:Alleles; D001477:Bartter Syndrome / Q000097:blood / Q000175:diagnosis* / Q000235:genetics*; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics; D004252:DNA Mutational Analysis; D005500:Follow-Up Studies; D006115:Greece; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011188:Potassium / Q000097:blood; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics*
chemical_list: C086989:KCNJ1 protein, human; D024661:Potassium Channels, Inwardly Rectifying; D011188:Potassium