Genes are listed alphabetically.

See Table A. Genes and Databases for chromosome locus and protein.

See Molecular Genetics for information on variants detected in this gene.

Sequence analysis detects variants that are benign, likely benign, of uncertain significance, likely pathogenic, or pathogenic. Variants may include small intragenic deletions/insertions and missense, nonsense, and splice site variants; typically, exon or whole-gene deletions/duplications are not detected. For issues to consider in interpretation of sequence analysis results, click here.

Gene-targeted deletion/duplication analysis detects intragenic deletions or duplications. Methods used may include a range of techniques such as quantitative PCR, long-range PCR, multiplex ligation-dependent probe amplification (MLPA), and a gene-targeted microarray designed to detect single-exon deletions or duplications.

In a study of ten families, nine had pathogenic variants in KCNQ1 [Tyson et al 2000]. Of 63 families, six (9.5%) had pathogenic variants in KCNE1 [Schwartz et al 2006]. None of the individuals of Norwegian ancestry with JLNS have been shown to have KCNE1 pathogenic variants [Tranebjærg et al 1999, Berge et al 2008, Siem et al 2008]. Pathogenic variants have been found in either KCNQ1 or KCNE1 in 94% of individuals with clinical JLNS undergoing molecular testing [Schwartz et al 2006].

Three variants in KCNE1, all detectable by Sanger sequencing, have been associated with JLNS [Schulze-Bahr et al 1997, Tyson et al 1997].

No deletions or duplications of KCNE1 have been reported to cause JLNS.

Sung et al [2014]

Both deletion and duplication of one or more exons of KCNQ1 are known to cause long QT syndrome [Zehelein et al 2006, Eddy et al 2008, Sung et al 2014]; their frequency is unknown.