Clinical characteristics.

Jervell and Lange-Nielsen syndrome (JLNS) is characterized by congenital profound bilateral sensorineural hearing loss and long QTc, usually >500 msec. Prolongation of the QTc interval is associated with tachyarrhythmias, including ventricular tachycardia, episodes of torsade de pointes ventricular tachycardia, and ventricular fibrillation, which may culminate in syncope or sudden death. Iron-deficient anemia and elevated levels of gastrin are also frequent features of JLNS. The classic presentation of JLNS is a deaf child who experiences syncopal episodes during periods of stress, exercise, or fright. Fifty percent of individuals with JLNS had cardiac events before age three years. More than half of untreated children with JLNS die before age 15 years.

Diagnosis/testing.

The diagnosis of JLNS is established in a child with congenital sensorineural deafness, long QT interval, and presence of biallelic pathogenic variants in either KCNQ1 or KCNE1.

Management.

Treatment of manifestations: Cochlear implantation to treat hearing loss; beta-adrenergic blockers for long QT interval (Note: Beta-blocker treatment is only partially effective.); implantable cardioverter defibrillators (ICDs) for those with a history of cardiac arrest and/or failure to respond to other treatments; ensure availability of automated external defibrillators where appropriate; standard treatment for those with iron-deficiency anemia.

Prevention of secondary complications: Special precautions during anesthesia are necessary because of the increased risk for cardiac arrhythmia.

Surveillance: Beta-blocker dose should be regularly assessed for efficacy and adverse effects, with evaluation every three to six months during rapid growth phases; periodic evaluations of ICDs for inappropriate shocks and pocket or lead complications.

Agents/circumstances to avoid: Drugs that cause further prolongation of the QT interval; activities known to precipitate syncopal events in persons with long QT syndrome.

Evaluation of relatives at risk: Hearing evaluation by standard newborn hearing screening programs and electrocardiograms for at-risk sibs; molecular genetic testing to confirm the diagnosis if the pathogenic variants in an affected family member are known.

Pregnancy management: Consideration should be given as to whether a mother who has a fetus affected with JLNS herself has long QT syndrome.

Other: Training for family members in cardiopulmonary resuscitation; use of an ID bracelet explaining the diagnosis; notifying local emergency medical services of high-risk persons with JLNS.

Genetic counseling.

JLNS is inherited in an autosomal recessive manner. Parents of a child with JLNS are usually heterozygotes; rarely, only one parent is heterozygous (i.e., the proband has one inherited and one de novo pathogenic variant). Parents may or may not have the long QT syndrome (LQTS) phenotype. At conception, each sib of an affected individual usually has a 25% chance of being affected with JLNS, a 50% chance of being a carrier of a JLNS-causing pathogenic variant and potentially at risk for LQTS, and a 25% chance of being unaffected and not a carrier. Carrier testing for at-risk relatives and prenatal testing for pregnancies at increased risk are possible if the pathogenic variants in the family are known.

Suggestive Findings

Jervell and Lange-Nielsen syndrome (JLNS) should be suspected in a proband with the following features:

• Profound congenital sensorineural deafness
• Long QTc interval (>500 msec), often manifest as syncope, most often elicited by emotion or exercise. Note: Normal QTc interval in males is <440 msec and in post-pubertal females is <460 msec.

Establishing the Diagnosis

The diagnosis of JLNS is established in a proband with the above suggestive findings. Identification of biallelic pathogenic (or likely pathogenic) variants in either KCNQ1 or KCNE1 confirms the diagnosis, particularly if clinical features are inconclusive.

Note: (1) It is not currently known how many children with molecularly confirmed JLNS have a borderline QTc interval (440-500 msec) or a normal QTc interval. (2) Hearing loss commonly occurs in individuals with long QT syndrome (LQTS). The hearing loss may be entirely unrelated to the etiology of the LQTS, particularly if the hearing loss is moderate. (3) Per ACMG/AMP variant interpretation guidelines, the terms "pathogenic variant" and "likely pathogenic variant" are synonymous in a clinical setting, meaning that both are considered diagnostic and can be used for clinical decision making [Richards et al 2015]. Reference to "pathogenic variants" in this section is understood to include likely pathogenic variants. (4) Identification of biallelic KCNQ1 or KCNE1 variants of uncertain significance (or of one known pathogenic variant and one variant of uncertain significance) does not establish or rule out the diagnosis.

Molecular genetic testing approaches can include serial single-gene testing, use of a multigene panel, and more comprehensive genomic testing:

• Serial single-gene testing. Sequence analysis of KCNQ1 is performed first and followed by gene-targeted deletion/duplication analysis if no pathogenic variant is found. If only one or no KCNQ1 pathogenic variant is identified, sequence analysis of KCNE1 should be performed next.
  In countries with KCNQ1 founder variants (e.g., Norway) KCNQ1 sequencing should be carried out with knowledge of these variants to ensure they will be detected (see Molecular Genetics) [Tranebjærg et al 1999, Tranebjærg 2004, Berge et al 2008, Siem et al 2008].
• A multigene panel that includes KCNE1, KCNQ1 and other genes of interest (see Differential Diagnosis) may also be considered. Note: (1) The genes included in the panel and the diagnostic sensitivity of the testing used for each gene vary by laboratory and are likely to change over time. (2) Some multigene panels may include genes not associated with the condition discussed in this GeneReview; thus, clinicians need to determine which multigene panel is most likely to identify the genetic cause of the condition while limiting identification of variants of uncertain significance and pathogenic variants in genes that do not explain the underlying phenotype. (3) In some laboratories, panel options may include a custom laboratory-designed panel and/or custom phenotype-focused exome analysis that includes genes specified by the clinician. (4) Methods used in a panel may include sequence analysis, deletion/duplication analysis, and/or other non-sequencing-based tests.
  For an introduction to multigene panels click here. More detailed information for clinicians ordering genetic tests can be found here.
• More comprehensive genomic testing (when available) including exome sequencing, mitochondrial sequencing, and genome sequencing may be considered. Such testing may provide or suggest a diagnosis not previously considered (e.g., mutation of a different gene or genes that results in a similar clinical presentation).
  For an introduction to comprehensive genomic testing click here. More detailed information for clinicians ordering genomic testing can be found here.

Clinical Description

The classic presentation of JLNS is a deaf child who experiences syncopal episodes during periods of stress, exercise, or fright.

Hearing loss. All individuals with molecularly confirmed JLNS have profound bilateral congenital sensorineural deafness (see Genetic Hearing Loss Overview).

Long QTc. Individuals with JLNS have a QTc interval greater than 500 msec (average 550 msec), indicating increased time for ventricular depolarization and repolarization [Winbo et al 2012, Winbo et al 2014]. Abnormal cardiac depolarization and repolarization may result in tachyarrhythmias (including ventricular tachycardia, episodes of torsade de pointes ventricular tachycardia, and ventricular fibrillation), which may culminate in syncope or sudden death.

QTc prolongation in JLNS, particularly when severe, appears to be associated with increased risk for death in infancy (SIDS). In the Schwartz et al [2006] study of 135 families with JLNS, the QTc was markedly prolonged (557±65 msec); 50% of individuals had cardiac events before age three years, with emotion and exercise being the primary triggers. Although more than half of untreated children with JLNS die before age 15 years, some individuals are reported to have survived several syncopal episodes during adulthood. Note, however, that selection bias for severely affected individuals cannot be excluded: individuals with putative JLNS but no clinical manifestations other than deafness until adulthood (and to age 50 years in one individual) have been described.

Anemia. Individuals with KCNQ1-related JLNS have an increased incidence of iron deficiency anemia and hypergastrinemia [Winbo et al 2013]. This may be due to loss of the KCNQ1 potassium channels and reduced gastric acid secretion.

Other. The sex ratio among individuals with JLNS is even, but females are at lower risk for cardiac arrest/sudden death [Schwartz et al 2006]. Vestibular dysfunction was found in 14/14 deaf individuals with JLNS, irrespective of previous cochlear implantation. The proposed mechanism was disruption of the endolymph homeostasis [Winbo & Rydberg 2015]

Physical examination is unremarkable except for deafness.

Heterozygotes. Individuals who are heterozygous for pathogenic variants associated with JLNS usually have normal hearing. In some heterozygotes, QTc prolongation, fainting, and sudden death never occur. In contrast, some individuals heterozygous for pathogenic variants associated with JLNS may have QTc prolongation associated with fainting and death heritable in an autosomal dominant manner. This form of LQTS is called Romano-Ward syndrome (RWS).

Histopathology of temporal bone. Histologic examination of a few temporal bones was performed prior to the availability of molecular genetic testing, but not since. In one Norwegian individual with JLNS resulting from homozygosity for the c.572_576del pathogenic variant in KCNQ1, histopathologic examination of the temporal bones showed severe atrophy of the stria vascularis and the organ of Corti with absence of cochlear nerve fibers [Tranebjærg L & Merchant SM, unpublished data (2012)].

Phenotype Correlations by Gene

Among six asymptomatic individuals reported by Schwartz et al [2006], two had biallelic KCNQ1 pathogenic variants and four had biallelic KCNE1 pathogenic variants, further confirming the milder presentation of JLNS associated with KCNE1 pathogenic variants compared to JLNS associated with KCNQ1 pathogenic variants.

KCNQ1. Individuals with KCNQ1-related JLNS have an increased incidence of iron deficiency anemia and hypergastrinemia [Winbo et al 2013].

Genotype-Phenotype Correlations

Among 63 individuals who were genotyped, 33% were compound heterozygotes [Schwartz et al 2006]. No clinical difference was evident between persons with at least one inactivating variant (e.g., insertion/deletion, splice variant, truncation) and those with missense variants.

Nomenclature

Lange-Nielsen syndrome has also been called cardioauditory syndrome of Jervell and Lange-Nielsen and surdo-cardiac syndrome.

JLNS is now appreciated to be a true syndrome, in which the cardiac and cochlear pathologies are attributable to a common molecular etiology. Although there are several case reports in the older literature of individuals with long QT syndrome and non-profound hearing loss, in many of these reports it is likely that the hearing loss and prolonged QT interval have different etiologies (see Differential Diagnosis).

Prevalence

Prevalence varies depending on the population studied:

• Norway has an unusually high prevalence of at least one in 200,000 [Tranebjærg et al 1999]. This prevalence stems from four Norwegian founder variants [Berge et al 2008, Siem et al 2008, Winbo et al 2012].
• Sweden also has a prevalence of one in 200,000 based on a study of preadolescent children, identifying 19 affected individuals from 13 families. Eight KCNQ1 pathogenic variants were identified, of which p.Arg518Ter constituted 12/24 alleles [Winbo et al 2012]. Founder variants accounted for 83% of pathogenic variants [Winbo et al 2014].
• In a study of 350 children with congenital deafness in Turkey, one in 175 had JLNS [Ocal et al 1997].
• A particular missense KCNQ1 variant has been identified in the heterozygous state in autosomal dominant LQTS and in the homozygous state in JLNS in a few individuals from Finland; however, prevalence of JLNS was not increased in Finland [Piippo et al 2001].
• An overview of worldwide occurrence was published by Tranebjærg [2004]

These data are the best available; however, diagnostic criteria using a QTc >440 msec in children are likely to include some false positives, perhaps as many as 15%-20% [Allan et al 2001]. The design of the review by Schwartz et al [2006] did not allow refinement of prevalence estimates.

Evaluations Following Initial Diagnosis

To establish the extent of disease and needs in an individual diagnosed with Jervell and Lange-Nielsen syndrome (JLNS), the following evaluations are recommended if they have not already been completed:

• Formal audiology evaluation for extent of hearing loss
• Cardiac examination including calculation of QTc
• A three-generation family history that focuses on cardiac disease, syncope, and hearing ability
• Complete blood count to screen for anemia. If anemia is present, screening for iron deficiency is recommended.
• Consultation with a clinical geneticist

Treatment of Manifestations

Hearing loss in JLNS may be treated successfully with cochlear implantation, an intervention that does not interfere with bipolar pacemakers [Green et al 2000, Chorbachi et al 2002] (see Genetic Hearing Loss Overview). To date, the cumulative published experience includes approximately 20 individuals with JLNS who have received cochlear implantation. Of note, the diagnosis of JLNS was only verified with molecular genetic testing in four Norwegian individuals, all of whom had pathogenic variants in KCNQ1. An increase in sound-related syncopal episodes was noted after cochlear implantation in one child [Al-Aama et al 2015].

Note: Although cochlear implantation appears to be safe, special precautions are necessary during anesthesia because of the increased risk for cardiac arrhythmia [Daneshi et al 2008, Siem et al 2008, Yanmei et al 2008]. One affected individual died during a perioperative cardiac arrest [Broomfield et al 2010].

Cardiac issues. The main goal in management of JLNS is prevention of syncope, cardiac arrest, and sudden death. Note that efficacy of beta-blocker treatment is only partial: 51% of treated individuals had cardiac events and 27% had cardiac arrest or sudden death. Even with additional therapies (e.g., pacemaker, implantable cardioverter/defibrillator, left sympathetic denervation), 18 (56%) of 32 individuals experienced additional symptoms, including sudden death in seven [Schwartz et al 2006].

• Administration of beta-adrenergic blockers has been the traditional first-line medical therapy for cardiac events, but more aggressive, immediate treatment may be appropriate. Cardiac events in JLNS frequently occur despite beta blockade [Schwartz et al 2006]. Goldenberg et al [2006] demonstrated markedly increased mortality in individuals with JLNS treated exclusively with beta-blockers in comparison to individuals with Romano-Ward syndrome. A mortality rate of 35% over five years was observed for individuals receiving beta-blockers exclusively; 86% of individuals treated exclusively with beta-blockers experienced a cardiac event. The interactions of beta-blockers with other medical conditions (e.g., asthma, diabetes mellitus, depression) should also be considered. Propranolol and nadolol have been shown to be more effective than metoprolol in suppressing cardiac events [Chockalingam et al 2012, Winbo et al 2014]. A recent consensus statement advocates use of nadolol as the preferred beta-blocker for drug therapy of individuals with long QT syndrome [Ackerman et al 2017].
• Implantable cardioverter defibrillators (ICDs) should be considered in individuals with a history of cardiac arrest or failure to respond to other treatments [Goel et al 2004]. More recent recommendations have strongly urged ICD placement for high-risk individuals, defined by the following criteria [Schwartz et al 2006]:
  • QTc interval >550 msec
  • Syncope before age five years
  • Male sex, age >20 years with KCNQ1 pathogenic variant
• The risk for sudden cardiac death appears to be low in individuals younger than age five years, but medical therapy should be administered early in these high-risk individuals and ICD placement considered after age five years [Richter & Brugada 2006].
• In certain cases, the availability of automated external defibrillators in the home, workplace, or school may be applicable, as is appropriate CPR training of family members and those who have regular contact with individuals with JLNS.
• Left cardiac sympathetic denervation has been effective for some individuals.

Iron deficiency anemia. The treatment of iron deficiency anemia should follow standard guidelines.

Prevention of Primary Manifestations

See Treatment of Manifestations regarding prevention of syncope, cardiac arrest, and sudden death.

Prevention of Secondary Complications

Special precautions during anesthesia are necessary because of the increased risk for cardiac arrhythmia [Daneshi et al 2008, Siem et al 2008, Yanmei et al 2008].

Surveillance

Beta-blocker dose should be regularly assessed for efficacy and adverse effects, and doses altered as needed. Because dose adjustment is especially important in growing children, evaluation is appropriate every three to six months during rapid growth phases.

Regular, periodic evaluation of implantable cardioverter defibrillators (ICDs) for inappropriate shocks and pocket or lead complications is indicated.

Agents/Circumstances to Avoid

The following should be avoided:

• Drugs that cause further prolongation of the QT interval or provoke torsade de pointes; see www.crediblemeds.org for a complete and updated list (registration required).
• Triggers for intense or sudden emotion; activities that are known to precipitate syncopal events in individuals with long QT syndrome, including:
  • Competitive sports
  • Amusement park rides
  • Frightening movies
  • Jumping into cold water

A cardiologist should make recommendations for activity restrictions based on the effectiveness of medical intervention.

Evaluation of Relatives at Risk

It is appropriate to evaluate sibs and parents of a proband in order to identify as early as possible those who would benefit from initiation of treatment and preventive measures.

• If the pathogenic variants in the family are known, molecular genetic testing can be used to clarify the genetic status of at-risk family members.
• If the pathogenic variants in the family are not known, EKG testing should be undertaken to evaluate for QT prolongation.
• Standard newborn screening programs are sufficient to identify hearing loss in children with JLNS.

Because of the relationship between JLNS and long QT syndrome, EKG should be considered for relatives at risk for JLNS even if they have normal hearing.

If the JLNS-causing pathogenic variants in an affected family member are known, molecular genetic testing of a relative with congenital profound sensorineural hearing loss is recommended to confirm the diagnosis of JLNS.

See Genetic Counseling for issues related to testing of at-risk relatives for genetic counseling purposes.

Pregnancy Management

Consideration should be given as to whether a mother who has a fetus affected with JLNS herself has long QT syndrome [Seth et al 2007].

Therapies Under Investigation

Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.

Other

Family members of individuals with JLNS should be trained in cardiopulmonary resuscitation (CPR) as up to 95% of individuals with JLNS have a cardiac event before adulthood [Schwartz et al 2006].

Affected individuals should wear an ID bracelet explaining their diagnosis.

It is appropriate to notify local emergency medical services (EMS) of high-risk persons, including those with JLNS [Hazinski et al 2004].

Mode of Inheritance

Jervell and Lange-Nielsen syndrome (JLNS) is inherited in an autosomal recessive manner.

Risk to Family Members

Parents of a proband

• Parents of a child with JLNS are usually obligate heterozygotes (i.e., carriers of one KCNQ1 or KCNE1 pathogenic variant). In rare cases, only one parent is heterozygous and the other pathogenic variant in the proband is de novo [Schwartz et al 2000].
• Parents may or may not have the long QT syndrome (LQTS) phenotype. Studies have documented autosomal dominant inheritance of moderately prolonged QTc intervals in some, but not all, families in which one or more sibs have JLNS [Splawski et al 1997].
• Recommendations for evaluation of the parents of a child with JLNS include:
  • Molecular genetic testing if the pathogenic variants have been identified;
  • Comprehensive electrocardiographic testing for evidence of QTc prolongation by a physician familiar with LQTS.

Sibs of a proband

• If both parents of the proband are heterozygous for a JLNS-related pathogenic variant (i.e., both of the variants identified in the proband are inherited), the typical risks at conception to each sib are:
  • A 25% chance of inheriting two pathogenic variants and being affected with JLNS;
  • A 50% chance of inheriting one pathogenic variant. A sib who inherits one pathogenic variant would not be expected to have JLNS but is at risk for LQTS if the inherited pathogenic variant is associated with the LQTS phenotype (approximately 67% of JLNS-associated pathogenic variants are also known to also be associated with autosomal dominant LQTS) [Al-Aama et al 2015];
  • A 25% chance of inheriting neither of the pathogenic variants identified in the proband. A sib who inherits neither of the JLNS-related pathogenic variants is not at increased risk for JLNS or, potentially, LQTS.
• If only one parent of the proband is heterozygous for a JLNS-related pathogenic variant (i.e., the proband has one inherited and one de novo pathogenic variant), sibs are not at increased risk for JLNS but 50% are potentially at risk for LQTS if the inherited pathogenic variant is associated with the LQTS phenotype.
• Recommendations for evaluation of sibs of a proband with JLNS include:
  • Audiology evaluation;
  • Electrophysiologic evaluation for evidence of LQTS;
  • Molecular genetic testing if the pathogenic variants in the proband are known;
  • Comprehensive electrocardiographic testing for evidence of QTc prolongation by a physician familiar with LQTS.

Offspring of a proband

• The offspring of an individual with JLNS inherit one pathogenic variant; thus, 100% of the proband's offspring are potentially at risk for LQTS.
• In the event that the reproductive partner of the proband is also heterozygous for a pathogenic variant in the same gene in which two pathogenic variants have been identified in the proband, the risk to offspring of having JLNS is 50%.
• Recommendations for evaluation of the offspring of an individual with JLNS include comprehensive electrocardiographic testing for evidence of QTc prolongation by a physician familiar with LQTS.

Other family members. Sibs of a proband's parents may also be at 50% risk of having a pathogenic variant in KCNQ1 or KCNE1 and at potential risk for LQTS.

Carrier (Heterozygote) Detection

Carrier testing for at-risk relatives requires prior identification of the KCNQ1 or KCNE1 pathogenic variants in the family.

Related Genetic Counseling Issues

See Management, Evaluation of Relatives at Risk for information on evaluating at-risk relatives for the purpose of early diagnosis and treatment.

Because prolonged QTc interval in families with JLNS may follow an autosomal dominant inheritance pattern, it is important that family members at risk undergo electrocardiographic testing for evidence of LQTS early in life. Individuals with LQTS are at increased risk for sudden death and thus require cardiologic intervention. The actual risk for LQTS in family members of individuals with JLNS is not known.

Individuals who are heterozygous for a JLNS-related pathogenic variant have a single pathogenic variant in a gene associated with LQTS that may cause QTc prolongation or LQTS in either a clinically significant or clinically insignificant form. Whether the variant is clinically significant or insignificant, it may be transmitted in a clinically significant fashion to future generations as either autosomal dominant LQTS (i.e., Romano-Ward syndrome) or JLNS, a confusing phenomenon during pedigree evaluation.

Family planning

• The optimal time for determination of genetic risk, clarification of genetic status, and discussion of the availability of prenatal/preimplantation genetic testing is before pregnancy.
• It is appropriate to offer genetic counseling (including discussion of potential risks to offspring and reproductive options) to young adults who are affected, are heterozygous, or are at risk of being heterozygous.

DNA banking. Because it is likely that testing methodology and our understanding of genes, pathogenic mechanisms, and diseases will improve in the future, consideration should be given to banking DNA from probands in whom a molecular diagnosis has not been confirmed (i.e., the causative pathogenic mechanism is unknown). For more information, see Huang et al [2022].

Prenatal Testing and Preimplantation Genetic Testing

Once the KCNQ1 or KCNE1 pathogenic variants have been identified in an affected family member, prenatal and preimplantation genetic testing are possible.

Differences in perspective may exist among medical professionals and in families regarding the use of prenatal testing. While most centers would consider use of prenatal testing to be a personal decision, discussion of these issues may be helpful.

Molecular Pathogenesis

Jervell and Lange-Nielsen syndrome (JLNS) is caused by an aberration in a potassium channel found in the stria vascularis of the cochlea (inner ear) and the heart. Note that a minority of pathogenic variants in KCNQ1 and KCNE1 cause JLNS; the majority cause LQTS (see Differential Diagnosis).

• KCNQ1 and KCNE1 encode the alpha and beta subunit proteins (K_VLQT1/minK) for the slow potassium current, I_Ks of the cochlea and the heart.
• When stimulated by sound, potassium from the scala media of the cochlea passes through the apex of the hair cells, depolarizing the hair cells and causing a calcium-channel-induced release of neurotransmitter onto the auditory nerve. Depolarizations of the auditory nerve are sent centrally where they are perceived as sound. The maintenance of high potassium concentration in the endolymphatic fluid of the inner ear is required for normal hearing. The potassium-rich fluid of the scala media is created by the I_Ks potassium channels (exclusively K_VLQT1/minK) in the stria vascularis.
• Malfunction in these channels in the cochlea causes deafness.
• Malfunction in these channels in the heart results in abnormal ventricular electrical activity and LQTS.

Author History

Shane M Daley, MD; Mayo Clinic-Scottsdale (2002-2010)

Glenn Edward Green, MD (2002-present)

Ricardo A Samson, MD (2002-present)

Lisbeth Tranebjærg, MD, PhD (2002-present)

Revision History

• 17 August 2017 (sw) Comprehensive update posted live
• 20 November 2014 (me) Comprehensive update posted live
• 4 October 2012 (me) Comprehensive update posted live
• 23 February 2010 (me) Comprehensive update posted live
• 19 March 2007 (me) Comprehensive update posted live
• 29 July 2004 (me) Comprehensive update posted live
• 13 January 2003 (gg) Revision: Molecular Genetic Testing
• 29 July 2002 (me) Review posted live
• 8 October 2001 (gg) Original submission

Published Guidelines / Consensus Statements

• American College of Medical Genetics. Genetics evaluation guidelines for the etiologic diagnosis of congenital hearing loss. Genetic evaluation of congenital hearing loss expert panel. Available online. 2002. Accessed 8-17-23.
• American College of Medical Genetics. Statement on universal newborn hearing screening. Available online. 2000. Accessed 8-17-23.

Literature Cited

• Ackerman MJ, Priori SG, Anne Dubin A, Kowey P, Linker NJ, Slotwiner D, Triedman J, Van Hare GF, Gold MR. Beta blocker therapy for long QT syndrome and catecholaminergic polymorphic ventricular tachycardia: are all beta blockers equivalent? Heart Rhythm. 2017;14:e41-e44. [PubMed: 27659101]
• Al-Aama JY, Al-Ghamdi S, Bdier AY, AlQarawi A, Jiman OA, Al-Aama N, Al-Aata J, Wilde AA, Bhuiyan ZA. Genotype-phenotype analysis of Jervell and Lange-Nielsen syndrome in six families from Saudi Arabia. Clin Genet. 2015;87:74-9. [PubMed: 24372464]
• Allan WC, Timothy K, Vincent GM, Palomaki GE, Neveux LM, Haddow JE. Long QT syndrome in children: the value of the rate corrected QT interval in children who present with fainting. J Med Screen 2001;8:178-82 [PubMed: 11743033]
• Baek JS, Bae EJ, Lee SY, Park SS, Kim SY, Jung KN, Noh CI (2010) Jervell and Lange-Nielsen syndrome: novel compound heterozygous mutations in the KCNQ1 in a Korean family. J Korean Med Sci. 25:1522-5. [PMC free article: PMC2946666] [PubMed: 20890437]
• Berge KE, Haugaa KH, Früh A, Anfinsen O-G, Gjjesdaj K, Siem G, Øyen N, Greve G, Carlsson A, Rognum TO, Hallerud M, Kongsgård E, Amlie JP, Leren TP. Molecular genetic analysis of long QT syndrome in Norway indicating a high prevalence of heterozygous mutation carriers. Scand J Clin Lab Invest 2008; 68:362-8 [PubMed: 18752142]
• Bhuiyan ZA, Momenah TS, Amin AS, Al-Khadra AS, Alders M, Wilde AA, Mannens MM (2008) An intronic mutation leading to incomplete skipping of exon-2 in KCNQ1 rescues hearing in Jervell and Lange-Nielsen syndrome. Prog Biophys Mol Biol. 98:319-27. [PubMed: 19027783]
• Broomfield SJ, Bruce IA, Henderson L, Green KMJ, Ramsden RT. Cochlear impantation in Jervell & Lange-Nielsen syndrome: a cautionary report. Cochlear Implants Int. 2010;11:163-5 [PubMed: 21756604]
• Chang RK, Lan YT, Silka MJ, Morrow H, Kwong A, Smith-Lang J, Wallerstein R, Lin HJ. Genetic variants for long QT syndrome among infants and children from a statewide newborn hearing screening program cohort. J Pediatr. 2014;164:590-5.e1-3. [PMC free article: PMC3943925] [PubMed: 24388587]
• Chockalingam P, Crotti L, Girardengo G, Johnson JN, Harris KM, van der Heijden JF, Hauer RNW, Beckmann BM, Spazzolini C, Rordorf R, Rydberg A, Clur SB, Fischer M, van den Heuvel F, Kaab S, Blom NA, Ackerman MJ, Schwartz PJ, Wilde AAM. Not All beta-blockers are equal in the management of long QT syndrome types 1 and 2. J Am Coll Cardiol 2012;60:2092-9. [PMC free article: PMC3515779] [PubMed: 23083782]
• Chorbachi R, Graham JM, Ford J, Raine CH. Cochlear implantation in Jervell and Lange-Nielsen syndrome. Int J Pediatr Otorhinolaryngol 2002;66:213-21 [PubMed: 12443809]
• Daneshi A, Ghassemi MM, Talee M, Hassanzadeh S. Cochlear implantation in children with Jervell and Lange-Nielsen syndrpome J Laryngol Otol 2008;122:314-7 [PubMed: 17498328]
• Eddy CA, MacCormick JM, Chung SK, Crawford JR, Love DR, Rees MI, Skinner JR, Shelling AN. Identification of large gene deletions and duplications in KCNQ1 and KCNH2 in patients with long QT syndrome. Heart Rhythm 2008; 5:1275-81 [PubMed: 18774102]
• Gao Y, Li C, Liu W, Wu R, Qiu X, Liang R, Li L, Zhang L, Hu D (2012) Genotype-phenotype analysis of three Chinese families with Jervell and Lange-Nielsen syndrome. J Cardiovasc Dis Res. 3:67-75. [PMC free article: PMC3354473] [PubMed: 22629021]
• Goel AK, Berger S, Pelech A, Dhala A (2004) Implantable cardioverter defibrillator therapy in children with long QT syndrome. Pediatr Cardiol. 25:370-8. [PubMed: 14994181]
• Goldenberg I, Moss AJ, Zareba W, McNitt S, Robinson JL, Qi M, Towbin JA, Ackerman MJ, Murphy L. Clinical course and risk stratification of patients affected with the Jervell and Lange-Nielsen syndrome. J Cardiovasc Electrophysiol 2006;17:1161-8 [PubMed: 16911578]
• Green JD, Schuh MJ, Maddern BR, Haymond J, Helffrich RA. Cochlear implantation in Jervell and Lange-Nielsen syndrome. Ann Otol Rhinol Laryngol Suppl 2000;185:27-8 [PubMed: 11140992]
• Hazinski MF, Markenson D, Neish S, Gerardi M, Hootman J, Nichol G, Taras H, Hickey R, OConnor R, Potts J, van der Jagt E, Berger S, Schexnayder S, Garson A Jr, Doherty A, Smith S, et al (2004) Response to cardiac arrest and selected life-threatening medical emergencies: the medical emergency response plan for schools: A statement for healthcare providers, policymakers, school administrators, and community leaders. Circulation. 109:278-91. [PubMed: 14707021]
• Hothi SS, Thomas G, Killeen MJ, Grace AA, Huang CL (2009) Empirical correlation of triggered activity and spatial and temporal re-entrant substrates with arrhythmogenicity in a murine model for Jervell and Lange-Nielsen syndrome. Pflugers Arch. 458:819-35. [PMC free article: PMC2719739] [PubMed: 19430811]
• Huang SJ, Amendola LM, Sternen DL. Variation among DNA banking consent forms: points for clinicians to bank on. J Community Genet. 2022;13:389-97. [PMC free article: PMC9314484] [PubMed: 35834113]
• Ning L, Moss AJ, Zareba W, Robinson J, Rosero S, Ryan D, Qi M. Novel compound heterozygous mutations in the KCNQ1 gene associated with autosomal recessive long QT syndrome (Jervell and Lange-Nielsen syndrome). Ann Noninvasive Electrocardiol 2003;8:246-50 [PMC free article: PMC6932064] [PubMed: 14510661]
• Ocal B, Imamoglu A, Atalay S, Ercan Tutar H (1997) Prevalence of idiopathic long QT syndrome in children with congenital deafness. Pediatr Cardiol. 18:401-5. [PubMed: 9326683]
• Ohno S, Kubota T, Yoshida H, Tsuji K, Makiyama T, Yamada S, Kuga K, Yamaguchi I, Kita T, Horie M (2008) A novel mutation associated with Jervell and Lange-Nielsen syndrome in a Japanese family. Circ J. 72:687-93. [PubMed: 18441444]
• Olesen MS, Bentzen BH, Nielsen JB, Steffensen AB, David JP, Jabbari J, Jensen HK, Haunsø S, Svendsen JH, Schmitt N (2012) Mutations in the potassium channel subunit KCNE1 are associated with early-onset familial atrial fibrillation. BMC Med Genet. 13:24. [PMC free article: PMC3359244] [PubMed: 22471742]
• Piippo K, Swan H, Pasternack M, Chapman H, Paavonen K, Viitasalo M, Toivonen L, Kontula K. A founder mutation of the potassium channel KCNQ1 in long QT syndrome: implications for estimation of disease prevalence and molecular diagnostics. J Am Coll Cardiol 2001;37:562-8 [PubMed: 11216980]
• Richards S, Aziz N, Bale S, Bick D, Das S, Gastier-Foster J, Grody WW, Hegde M, Lyon E, Spector E, Voelkerding K, Rehm HL, et al. Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med. 2015;17:405-24. [PMC free article: PMC4544753] [PubMed: 25741868]
• Richter S, Brugada P. Risk-stratifying Jervell and Lange-Nielsen syndrome from clinical data. J Cardiovasc Electrophysiol 2006;17:1169-71 [PubMed: 16987380]
• Schulze-Bahr E, Wang Q, Wedekind H, Haverkamp W, Chen Q, Sun Y, Rubie C, Hördt M, Towbin JA, Borggrefe M, Assmann G, Qu X, Somberg JC, Breithardt G, Oberti C, Funke H. KCNE1 mutations cause jervell and Lange-Nielsen syndrome. Nat Genet. 1997;17:267-8. [PubMed: 9354783]
• Schwartz PJ, Priori SG, Dumaine R, Napolitano C, Antzelevitch C, Stramba-Badiale M, Richard TA, Berti MR, Bloise R. A molecular link between the sudden infant death syndrome and the long-QT syndrome. N Engl J Med 2000;343:262-7 [PubMed: 10911008]
• Schwartz PJ, Spazzolini C, Crotti L, Bathen J, Amlie JP, Timothy K, Shkolnikova M, Berul CI, Bitner-Glindzicz M, Toivonen L, Horie M, Schulze-Bahr E, Denjoy I. The Jervell and Lange-Nielsen syndrome: natural history, molecular basis, and clinical outcome. Circulation 2006;113:783-90 [PubMed: 16461811]
• Seth R, Moss AJ, McNitt S, Zareba W, Andrews ML, Qi M, Robinson JL, Goldenberg I, Ackerman MJ, Benhorin J, Kaufman ES, Locati EH, Napolitano C, Priori SG, Schwartz PJ, Towbin JA, Vincent GM, Zhang L. Long QT syndrome and pregnancy. J Am Coll Cardiol. 2007;49:1092-8. [PubMed: 17349890]
• Siem G, Früh A, Leren TP, Heimdal K, Teig E, Harris S. Jervell and Lange-Nielsen syndrome in Norwegian children: Aspects around cochlear implantation, hearing, and balance. Ear Hear 2008;29:261-9 [PubMed: 18595190]
• Splawski I, Timothy KW, Vincent GM, Atkinson DL, Keating MT. Molecular basis of the long-QT syndrome associated with deafness. N Engl J Med 1997;336:1562-7 [PubMed: 9164812]
• Sung JY, Bae EJ, Park S, Kim SY, Hyun YJ, Park SS, Seong MW. Large deletion in KCNQ1 identified in a family with Jervell and Lange-Nielsen syndrome. Ann Lab Med. 2014;34:395-8. [PMC free article: PMC4151011] [PubMed: 25187895]
• Thomas G, Killeen MJ, Gurung IS, Hakim P, Balasubramaniam R, Goddard CA, Grace AA, Huang CL (2007) Mechanisms of ventricular arrhythmogenesis in mice following targeted disruption of KCNE1 modelling long QT syndrome 5. J Physiol. 578:99-114. [PMC free article: PMC2075126] [PubMed: 17095567]
• Towbin JA, Wang Z, Li H. Genotype and severity of long QT syndrome. Drug Metab Dispos. 2001;29:574–9 [PubMed: 11259355]
• Tranebjærg L. Jervell and Lange-Nielsen syndrome. In: Willems PJ, ed. Genetic Hearing Loss. New York, NY: Marcel Dekker Publications; 2004:117-34.
• Tranebjærg L, Bathen J, Tyson J, Bitner-Glindzicz M. Jervell and Lange-Nielsen syndrome: a Norwegian perspective. Am J Med Genet 1999;89:137-46 [PubMed: 10704188]
• Tyson J, Tranebjaerg L, Bellman S, Wren C, Taylor JF, Bathen J, Aslaksen B, Sørland SJ, Lund O, Malcolm S, Pembrey M, Bhattacharya S, Bitner-Glindzicz M. IsK and KvLQT1: mutation in either of the two subunits of the slow component of the delayed rectifier potassium channel can cause Jervell and Lange-Nielsen syndrome. Hum Mol Genet. 1997;6:2179-85. [PubMed: 9328483]
• Tyson J, Tranebjærg L, McEntagart M, Larsen LA, Christiansen M, Whiteford ML, Bathen J, Aslaksen B, Sorland SJ, Lund O, Pembrey ME, Malcolm S, Bitner-Glindzicz M. Mutational spectrum in the cardioauditory syndrome of Jervell and Lange-Nielsen. Hum Genet 2000;107:499-503 [PubMed: 11140949]
• Wang RR, Li N, Zhang YH, Wang LL, Teng SY, Pu JL (2011) Novel compound heterozygous mutations T2C and 1149insT in the KCNQ1 gene cause Jervell and Lange-Nielsen syndrome. Int J Mol Med. 28:41-6. [PubMed: 21380488]
• Wang Z, Li H, Moss AJ, Robinson J, Zareba W, Knilans T, Bowles NE, Towbin JA. Compound heterozygous mutations in KvLQT1 cause Jervell and Lange-Nielsen syndrome. Mol Genet Metab 2002;75:308-16 [PubMed: 12051962]
• Winbo A, Stattin EL, Diamant UB, Persson J, Jensen SM, Rydberg A Prevalence, mutation spectrum, and cardiac phenotype of the Jervell and Lange-Nielsen syndrome in Sweden. Europace. 2012;14:1799-806. [PubMed: 22539601]
• Winbo A, Sandström O, Palmqvist R, Rydberg A Iron-deficiency anaemia, gastric hyperplasia, and elevated gastrin levels due to potassium channel dysfunction in the Jervell and Lange-Nielsen Syndrome. Cardiol Young. 2013;23:325-34. [PubMed: 22805636]
• Winbo A, Stattin E-L, Nordin C, Diamant UB, Persson J, Jensen SM, Rydberg A. Phenotype, origin and estimated prevalence of a common long QT syndrome mutation: a clinical, genealogical and molecular genetics study including Swedish R518X/KCNQ1 families. BMC Cardiovasc Disord. 2014;14:22 [PMC free article: PMC3942207] [PubMed: 24552659]
• Winbo A, Rydberg A (2015) Vestibular dysfunction is a clinical feature of Jervell and Lange-Nielsen Syndrome. Scand Cardiovasc J 2015; 49:7-13 [PubMed: 25471708]
• Yanmei F, Yagin W, Haibo S, Huiqun Z, Zhengnong C, Dongzhen Y, Shankai Y. Cochlear implantation in patients with Jervell and Lange_Nielsen syndrome, and a review of the literature. Int J Pediatr Otorhinolaryngol. 2008;72:1723-9 [PubMed: 18805595]
• Zehelein J, Kathoefer S, Khalil M, Alter M, Thomas D, Brockmeier K, Ulmer HE, Katus HA, Koenen M. Skipping of exon 1 in the KCNQ1 gene causes Jervell and Lange-Nielsen Syndrome. J Biol Chem 2006; 281:35397-403 [PubMed: 16987820]
• Zhang S, Yin K, Ren X, Wang P, Zhang S, Cheng L, Yang J, Liu JY, Liu M, Wang QK (2008) Identification of a novel KCNQ1 mutation associated with both Jervell and Lange-Nielsen and Romano-Ward forms of long QT syndrome in a Chinese family. BMC Med Genet. 9:24. [PMC free article: PMC2322962] [PubMed: 18400097]