KCNH2 Variant R681W Detail

We estimate the penetrance of LQTS for KCNH2 R681W is 12%. This variant was found in a total of 1 carriers in 0 papers or gnomAD, 0 had LQTS. R681W is present in 1 alleles in gnomAD. R681W has not been functionally characterized. This residue is located in a Non_Hotspot region for LQT2. In silico predictions, functional data (if available), and location in structure are equivalent to observing 1 individuals with LQT2 and 9 unaffected individuals.These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 R681W around 12% (1/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-6.181 1.0 -3 0.613 7
PROVEAN scores less than -2 are considered deleterious. REVEL scores higher than 0.5 or 0.75 are considered likely pathogenic (higher sensitivity with the former cutoff, higher specificity with the latter cutoff). A PolyPhen-2 score of 0.85 or greater is considered likely pathogenic. BLAST-PSSM reflects the evolutionary conservation of residue substitutions, more negative numbers indicate fewer observations of the specific substitution than is expected. Penetrance density is our previously published method to calculate the average LQTS probability density in a shell of residues surrounding a residue of interest (Kroncke et al. 2019).

Reported Carrier Data

PubMed ID Year Carriers Unaffected LQT2 Other Disease
LITERATURE, COHORT, AND GNOMAD: - 1 1 0 -
VARIANT FEATURES ALONE: - 10 9 1 -
Summary totals might not agree with the literature table because of duplicate patients, which were excluded from the total counts. We do not distinguish here between multiple missense codons. Missense variants are combined across degenerate codon substitutions since codon-level data were not consistently available for curation.

R681W has 50 previously observed neighbors within 15 angstroms

A residue within a folded protein on average has nearest neighbors that fall roughly into two shells: a "nearest" neighbor around 5-6 angstroms and a second shell around 11 angstroms. NOTE: some residues appear multiple times at different distances since the functional KV11.1 channel (protein product of KCNH2/hERG) is a homotetramer and occasionally the same residue from multiple subunits is present within the 15A window. All variants shown in the rightmost column have been observed in at least one individual in the literature or gnomAD.

Neighbor Distance (Angstroms) Variants Observed in Individuals
681 0 R681W,
677 5 M677T,
678 5
680 6
682 7 E682X,
685 7 R685P, R685C, R685H,
684 7
544 8 E544A, E544fsX,
698 8 E698X, E698K,
694 9 R694H, R694C,
545 9
674 9 H674fsX, H674Y,
683 9
679 10 R679W, R679Q,
675 10
676 10 Q676X, Q676fsX,
673 10
701 10
697 10 L697X,
546 11
543 11 S543fsX,
3 11
689 11
702 11
665 12 R665Q,
686 12
540 13 D540fsX,
716 13 V716G,
711 13 I711V,
666 13
687 13
688 13
709 13
5 13
695 13
541 13 R541H, R541C,
547 14 A547T,
699 14 E699D, E699D,
693 14 L693X,
691 14
4 14
690 14
548 14
668 14 S668L,
549 14 V549M,
720 14
671 14 A671Del, A671G,
705 15 W705fsX, W705X,
713 15 M713V,
710 15