title: Large deletion in KCNQ1 identified in a family with Jervell and Lange-Nielsen syndrome.
abstract: Long QT syndrome (LQTS) is a genetically heterogeneous disorder associated with sequence variations in more than 10 genes; in some cases, it is caused by large deletions or duplications among the main, known LQTS-associated genes. Here, we describe a 14-month-old Korean boy with congenital hearing loss and prolonged QT interval whose condition was clinically diagnosed as Jervell and Lange-Nielsen syndrome (JLNS), a recessive form of LQTS. Genetic analyses using sequence analysis and multiplex ligation-dependent probe amplification (MLPA) assay revealed a large deletion spanning exons 7-10 as well as a frameshift mutation (c.1893dup; p.Arg632Glnfs*20). To our knowledge, this is the first report of a large deletion in KCNQ1 identified in JLNS patients. This case indicates that a method such as MLPA, which can identify large deletions or duplications needs to be considered in addition to sequence analysis to diagnose JLNS.
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Ji Yeon
authors.initials: JY
authors.lastname: Sung
authors.affiliation: Department of Pediatrics, Seoul National University Hospital, Seoul, Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Bae
authors.affiliation: Green Cross Laboratories, Seoul, Korea.
authors.forename: Seungman
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Laboratory Medicine, National Medical Center, Seoul, Korea.
authors.forename: So Yeon
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Ye Jin
authors.initials: YJ
authors.lastname: Hyun
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Sung Sup
authors.initials: SS
authors.lastname: Park
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Moon-Woo
authors.initials: MW
authors.lastname: Seong
mesh_terms: D000293:Adolescent; D000483:Alleles; D001483:Base Sequence; D004562:Electrocardiography; D005091:Exons; D016368:Frameshift Mutation; D006579:Heterozygote; D006801:Humans; D029593:Jervell-Lange Nielsen Syndrome / Q000175:diagnosis / Q000235:genetics*; D051657:KCNQ1 Potassium Channel / Q000235:genetics*; D008297:Male; D021141:Nucleic Acid Amplification Techniques; D010375:Pedigree; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion
chemical_list: D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human
keywords: Exon deletion; Jervell and Lange-Nielsen syndrome; KCNQ1 mutation; Multiplex ligation-dependent probe amplification