Large Deletion in KCNQ1 Identified in a Family with Jervell and Lange-Nielsen Syndrome

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.

Síndrome de Jervell y Lange-Nielsen / Jervell and Lange-Nielsen Syndrome

El síndrome de Jervell y Lange-Nielsen es una forma poco frecuente de síndrome de QT largo. Su herencia es autosómica recesiva y se manifiesta con sordera neurosensorial. Revisamos el caso de una niña de 7 años implantada coclear bilateral. Tras un episodio sincopal se realiza el diagnóstico de síndrome de QT largo, el estudio genético confirma el diagnóstico. Recomendamos realizar electrocardiograma a todos los niños con hipoacusia severa con el objeto de descartar este síndrome.

The Jervell and Lange-Nielsen (JLNS) is an uncommon form of long QT syndrome. His inheritance is autosomal recessive and manifests as a sensorineural deafness. We review the case of a 7 year old girl bilateral cochlear implanted. After a syncope episode, a long QT syndrome was confirmed by genetic study. We recommend electrocardiogram (ECG) to all children with severe hearing loss in order to rule out this syndrome.

Jervell and Lange-Nielsen Syndrome: Novel Compound Heterozygous Mutations in the KCNQ1 in a Korean Family

The Jervell and Lange-Nielsen syndrome (JLNS) is an autosomal recessive syndrome characterized by congenital deafness and cardiac phenotype (QT prolongation, ventricular arrhythmias, and sudden death). JLNS has been shown to occur due to homozygous mutation in KCNQ1 or KCNE1. There have been a few clinical case reports on JLNS in Korea; however, these were not confirmed by a genetic study. We identified compound heterozygous mutations in KCNQ1 in a 5-yr-old child with JLNS, who visited the hospital due to recurrent syncope and seizures and had congenital sensorineural deafness. His electrocardiogram revealed a markedly prolonged corrected QT interval with T wave alternans. The sequence analysis of the proband revealed the presence of novel compound heterozygous deletion/splicing error mutations (c.828-830 delCTC, p.S277del/c.921G>A, p.V307V). Each mutation in KCNQ1 was identified on the maternal and paternal side. With beta-blocker therapy the patient has remained symptom-free for three and a half years.

Jervell-Lange Nielsen syndrome in a family with the long QT Syndrome (LQTS).

A child with Jervell-Lange Nielsen syndrome is presented from Kolkata. Family study showed that the other family members are suffering from long QT syndrome. The child had frequent syncopal attack and very prolonged QT interval requiring left cardiac sympathetic denervation and beta-blocker therapy as patient could not afford implantable defibrillator and cardiac pacing.