title: The homozygous KCNQ1 gene mutation associated with recessive Romano-Ward syndrome.
abstract: In a 7-year-old boy with normal hearing suffering from repeated syncope an extremely prolonged QTc interval (up to 700 ms) was found. The mother was completely asymptomatic and the father had an intermittently borderline QTc interval (maximum 470 ms) but no symptoms. In the proband a mutation analysis of KCNQ1 gene revealed a homozygous 1893insC mutation. The parents were heterozygous for this mutation. There was no consanguineous marriage in the family. The clinical relevance of these findings is that apparently normal individuals may have a latent reduction of repolarizing currents, a "reduced repolarization reserve," because they are carriers of latent ion channel genes mutations.
authors.affiliation: Department of Internal Medicine and Cardiology, University Hospital Brno, Brno, Czech Republic. novotny-t@seznam.cz
authors.forename: Tomas
authors.initials: T
authors.lastname: Novotny
authors.forename: Jitka
authors.initials: J
authors.lastname: Kadlecova
authors.forename: Jan
authors.initials: J
authors.lastname: Janousek
authors.forename: Renata
authors.initials: R
authors.lastname: Gaillyova
authors.forename: Alexandra
authors.initials: A
authors.lastname: Bittnerova
authors.forename: Alena
authors.initials: A
authors.lastname: Florianova
authors.forename: Martina
authors.initials: M
authors.lastname: Sisakova
authors.forename: Ondrej
authors.initials: O
authors.lastname: Toman
authors.forename: Karel
authors.initials: K
authors.lastname: Chroust
authors.forename: Ivo
authors.initials: I
authors.lastname: Papousek
authors.forename: Jindrich
authors.initials: J
authors.lastname: Spinar
mesh_terms: D001483:Base Sequence; D002648:Child; D004562:Electrocardiography / Q000379:methods; D005808:Genes, Recessive / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D051657:KCNQ1 Potassium Channel / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D029597:Romano-Ward Syndrome / Q000175:diagnosis* / Q000235:genetics*
chemical_list: D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human