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 in deaf school children population

To identify the patients of Jervell and Lange-Nielsen syndrome [JLNS] amongst congenitally deaf children. This was a cross-sectional study, conducted at Hamza Foundation Academy for the Deaf, and Combined Military Hospital Lahore over a period of 4 months from February to May 2012. A total of 379 children with congenital sensorineural hearing loss were included in this study. Echocardiographs of all children [ages 4-18 years] were obtained. The corrected QT [QTc] intervals of all 379 ECGs were calculated using the Bazett's formula. Using the Schwartz's criteria, patients with long QTc intervals were further evaluated for Jervell and Lange-Nielsen Syndrome. Out of 379 children, 84 [22.1%] were found to have QTc intervals equal to or longer than 0.44 seconds. As per Schwartz's criteria, 31 [36.9%] out of 84 children with Long QTc [8.17% in sample population], scored high points [4.0 to 6.0], proving presence of JLNS. A sizable proportion of congenitally deaf children had Jervell and Lange-Nielsen Syndrome in our study

Anthropometric profi les of children with congenital heart disease.

Background: Undernutrition is a common cause of morbidity in children with CHD. Previous data from developing country showed prevalence of preoperative undernutrition in children with CHD was up to 45%. The aim of this study are to determine the anthropometric profiles and prevalence of undernutrition in children with CHD by using the anthropometric measurement. Methods: A cross-sectional study was carried out in children aged 0-2 years old with CHD in Cipto Mangunkusumo hospital. All patients underwent an anthropometric evaluation (weight, length and head circumference) at presentation. Undernutrition, failure to thrive /FTT, short stature and microcephaly were determined according to WHO, weight-for-length, weight-for-age at 2 points, length-for-age, head circumference-for-age z-score < -2SD accordingly. Results: We had total of 95 patients, 73 patients with acyanotic and 22 patients with cyanotic lesions. Prevalence of undernutrition in CHD was 51.1%, with 22.3% severe undernutrition. FTT was found in 64.9%, short stature in 49.5% and microcephaly in 37% patients. FTT was found higher in acyanotic (72.2%) compared to cyanotic lesions (42.9%). In acyanotic, weight was affected more than length (72.2% vs 49.3%). In cyanotic, weight and length affected equally (42.9% vs 54.5%). Diet counseling were done in patients with undernutrition. Medicines, transcatheter or surgery intervention were indicated in selected patients. Conclusions: Prevalence of FTT was higher than undernutrition in children with CHD. FTT was found higher in acyanotic lesions. In acyanotic, weight was affected more than length. In cyanotic, weight and length affected equally.

Prevalence of long QT syndrome and other cardiac defects in deaf-mute children

Long QT syndrome is considered a fatal disease because of its association with ventricular arrhythmias and sudden cardiac death. Objectives of study were to determine the prevalence of long QT syndrome and other heart diseases, in deaf-mute children. A Cross-sectional descriptive study was conducted at Cholistan special education centre and Cardiology department, Sheikh Zayed hospital Rahim Yar Khan, Pakistan in September 2006. A total of 104 congenitally deaf-mute children were assessed. Height, weight and blood pressure measured, 12-lead electrocardiogram done and QTc calculated using Bazette's formula. Children with prolonged QTc underwent 24-hour ambulatory ECG recording. All were auscultated following complete protocol. A child with murmur was further evaluated with colour Doppler echocardiography. Audiometry was performed on all the children and the result interpreted according to WHO recommendations. Diagnosis of LQTS was based on Revised Schwartz criteria. Out of 104 children, 62 were male with mean age 11.89 yrs. The average systolic and diastolic BP was 97/67 mmHg. Average height was 126 Cm. All children had moderate to severe bilateral sensorineural hearing loss [40-80 dB]. One child had associated Patent Ductus Arteriosis. Fifteen had an innocent murmur. Prevalence of congenital heart disease was found to be 0.1/1000. Four children had QT interval more than 440 mSec, [range 0.46-0.47 mSec.]. Both genders were equally affected. Three children had high probability of LQTS and one had intermediate probability. Screening of family of these 4 patients showed prolonged QT interval in the sibling of one patient. Our study highlights the significant prevalence of Jervell Lange-Nielsen Syndrome in Pakistani deaf-mute children, which may be associated to the high level of consanguinity in this region. Awareness of this syndrome among health care providers is needed as timely diagnosis and subsequent treatment may prevent fatal complications.

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.

Fórmulas para el QT corregido y consideraciones clínicas

La medición del intervalo QT y QT corregido es importante en el seguimiento de pacientes cardiópatas así como de aquellos que reciben medicamentos que de una u otra forma afectan dicho intervalo. Se revisan las fórmulas más conocidas para el cálculo del QT corregido y se estudia su aplicación clínica

The measurement of the interval QT and corrected QT is important in the follow-up of cardiac patients as well as from those who receive medicines which of one or another form affect this interval. The most well-known formulas for the calculation of the corrected QT are reviewed and its clinical application are studied

Detección de una mutación en el gen KCNQ1 (KvLQT1) causante de síndrome de Jervell, Lange-Nielsen en una familia mexicana / KCNQ 1 (KvLQT1) missense mutation causing congenital long QT syndrome (Jervell-Lange-Nielsen) in a Mexican family

BACKGROUND: Long QT syndromes (LQTS) are inherited cardiac disorders caused by mutations in the genes that encode sodium or potassium transmembrane ion channel proteins. More than 200 mutations, in at least six genes, have been found in these patients. The Jervell and Lange-Nielsen (JLN) syndrome is the recessive form of the disease and is associated with deafness. Few families with JLN syndrome and genetic studies are reported in the literature. METHODS: The KCNQ1 (KvLQT1) gene in a Mexican family with Jervell-Lange-Nielsen long QT syndrome was analyzed using an automated sequence method. RESULTS: A missense mutation was found in the three affected individuals. This mutation is associated with complete loss of channel function. Correlation with the phenotype showed a prolonged QTc interval and deafness in the two siblings homozygous to the mutation. The mother, who was heterozygous for the mutation, also had prolonged QTc interval without deafness. The father and younger brother had normal QTc intervals. The mutation was not found in 50 healthy controls studied. CONCLUSIONS: We describe for the first time a mutation in the KCNQ1 gene in a Mexican family with JLN long QT syndrome. This mutation produces an amino acid change (Gly-Arg) at protein level at the 168 residue. This mutation has been previously reported in Caucasian families with LQTS.

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.

Relationship between congenital long QT syndrome and Brugada syndrome gene mutation / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the molecular pathology in families with long QT syndrome (LQTS) including Jervell-Longe-Nielsen syndrome (JLNS) and Romano-ward syndrome (RWS) and Brugada syndrome (BS) in Chinese population.</p><p><b>METHODS</b>Polymerase chain reaction and DNA sequencing were used to screen for KCNQ1, KCNH2, KCNE1, and SCN5A mutation.</p><p><b>RESULTS</b>We identified a novel mutation N1774S in the SCN5A gene of the BS family, a novel mutation G314S in a RWS family which had also been found in Europe, North America, and Japan, and a single nucleotide polymorphisms (SNPs) G643S in the KCNQ1 of the JLNS family. In this JLNS family, another heterozygous novel mutation in exon 2a was found in KCNQ1 of the patients.</p><p><b>CONCLUSION</b>New mutations were found in our experiment, which expand the spectrum of KCNQ1 and SCN5A mutations that cause LQTS and BS.</p>

Heterozygous mutation in KCNQ1 cause Jervell and Lange-Nielsen syndrome / 中华心血管病杂志

<p><b>OBJECTIVE</b>Jervell and Lange-Nielsen syndrome (JLNS) is a severe cardioauditory syndrome manifested as QT interval prolongation, abnormal T waves, and relative bradycardia ventricular tachyarrhythmias. In this report, we screened a nonconsanguineous families with JLNS for mutations in KCNQ1.</p><p><b>METHODS</b>Mutation analysis was performed by using purified PCR products to direct sequence analysis on an ABI-3730XL automated DNA sequencer. The whole sequence of proband' KCNQ1 was screened firstly, then screened the mutation exon sequences of others of the family and 50 unrelated normal persons.</p><p><b>RESULTS</b>A heterogeneous mutation was identified in the patients of the JLNS family, a missense mutation (G-->T) at nucleotide 917 encoded in exon 6 of KCNQ1. This substitution leads to a change from glycine to Valine at codon 306(G306V) corresponding to the S5 transmembrane segment of KCNQ1. The other normal members of the family and 50 unrelated normal persons were not identified this mutation.</p><p><b>CONCLUSION</b>The result suggested that not only homozygous mutations or compound heterozygous mutations in KCNQ1 could cause Jervell-Lange-Nielsen syndrome, the single heterozygous mutation may also cause Jervell-Lange-Nielsen syndrome.</p>

Prevalence of idiopathic long QT syndrome in congenital sensori-neural hearing loss students of Songkhla School for the Deaf.

OBJECTIVES: To survey the prevalence of the long QT syndrome (LQTS), especially Jervell-Lange-Nielsen syndrome (JLNS), in Thai children (The first such study). BACKGROUND: LQTS is a rare inherited disease with a prevalence of 0.21 per cent in children with congenital deafness from other reports. These patients carry a high risk of recurrent syncope and fatal ventricular arrhythmia. STUDY DESIGN: Cross-sectional survey from January 2000 to August 2000. METHOD: A total of 276 children with congenital sensori-neural hearing loss were included. A questionnaire was employed and all children were examined by a pediatric cardiologist to rule out organic heart disease. EKGs were obtained and QTc intervals were blindly measured using standard methods in L2, V5 or any other leads with the longest QTc interval by three pediatric cardiologists. If QTc interval is prolonged, additional EKG (up to 3) were done to confirm the finding. Schwartz criteria was used to identify index cases with LQTS after repeated EKGs, and exercise stress tests. Also, echocardiography were done in patients suspected of having LQTS. RESULTS: A total of 14 children needed a third EKG and more work ups due to persistent long QTc interval after 2 consecutive EKG studies with QTc intervals ranged from 456 msec to 466 msec, and Schwartz score from 1.5 to 2.5. There were 6 twins and no triplets in the study. Finally, two subjects (not twins or siblings) had persistent prolonged QTc intervals after 3 EKG studies. After the exercise stress test, both still had a prolonged QTc interval, not corrected to the normal QTc interval even at the exercise peak. There was no cardiac abnormality either structurally or functionally from the 2D echocardiogram and Doppler color flow study. CONCLUSION: The possible prevalence of JLNS was 0.7 per cent (2/276). Both children were in the low-risk group for having LQTS.

A Case of Congenital Long QT Syndrome with Reccurent Syncope

Congenital long QT syndrome (LQTS) is a disease characterized by prolongation of ventricle repolarization and by the occurrence, usually during emotional or physical stress, of life-threatening arrhythmias that lead to sudden death in most symptomatic and untreated patients. Two variants have been initially identified:the original Jervell and Lange-Nielsen syndrome of congenital deafness and autosomal recessive inheritance, and the more frequent Romano-Ward syndrome of autosomal dominant inheritance. Evidence also shows that approximately 25 to 30% of the cases are sporadic with syncope and a prolonged QT interval but without showing evidence for familial involvement. Familial and sporadic cases have been grouped under the definition of congenital long QT syndrome. We experienced a case of congenital long QT syndrome in a 13-year-old female girl. She had episodes of recurrent syncope and QT interval prolongation(QTc=0.46sec) in electrocardiogram(ECG). The ECG of her mother showed QT interval prologation(QTc=0.46sec). After applying atenolol, the QT interval returned to normal range and syncope has not occurred. We report a case of congenital long QT syndrome with a brief review of related literatures.

A Case of Congenital Long QT Syndrome Associated with Deafness and Syncope

Congenital long QT syndrome (LQTS) is an inherited disease characterized by prolonged QT intervals and polymorphic ventricular tachycardia. The clinical manifestations vary from sudden cardiac death by ventricular arrhythmia to asymptom throughout life. In 1957, Jervell and Lange-Nielsen reported a syndrome of congen-ital sensory deafness associated with a prolonged QT interval in four children. The affected children had multiple syncopal episodes, and three died suddenly. The mode of inheritance is autosomal recessive. Affected persons are susceptible to recurrent syncope, and they have a high incidence of sudden death and short life expectancy. We report a case and review the literature on long QT syndrome diagnosed in a 30-year-old female with a history of convulsion and loss of consciousness during delivery.