KCNH2 Variant E637G

Summary of observed carriers, functional annotations, and structural context for KCNH2 E637G. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT2 penetrance

54%

90% CI: 32.6% – 75.0%

7/14 effective observations

Total carriers

4

4 LQT2 · 0 unaffected

Functional studies

1

Publications with functional data

E637G has not been reported in gnomAD. This residue resides in a Hotspot region for LQT2.

We have tested the trafficking efficiency of this variant: 0% of WT with a standard error of 1%. In our analysis we used SE < 20% as 'high quality'. Approximately below 50% of WT is considered PS3 moderate and below 30% is PS3 strong.

Variant features alone are equivalent to phenotyping 3 individuals with LQT2 and 7 unaffected individuals.

In silico predictors

Variant-level computational predictors.
PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density LQT2 (%)
-6.767 0.999 -2 0.865 93

PROVEAN scores below -2 suggest deleterious impact. REVEL scores above 0.5–0.75 are often interpreted as likely pathogenic. PolyPhen-2 scores above 0.85 are typically pathogenic. BLAST-PSSM reflects evolutionary conservation; more negative values indicate rarer substitutions. Penetrance density summarises neighbouring residue risk (Kroncke et al. 2019).

Reported carrier data

Observed carriers by publication or cohort.
Source Year Carriers Unaffected LQT2 Other Disease
21216356 2011 1 0 1
21109023 2011 3 0 3
Literature, cohort, and gnomAD 4 0 4
Variant features alone 10 7 3

Totals may differ from individual publications due to duplicate patients removed during curation.

Functional data

Functional assay results from published electrophysiology studies. Steady state (S.S.) and peak tail current are relative % to wildtype (100% being no different from wildtype). V1/2 activation and inactivation are the voltages at which half of the maximal current is reached, in mV. Recovery from inactivation and deactivation time are ratios of characteristic time constants with wildtype. HM indicates homomeric channels, HT indicates heteromeric channels.

Homomeric channel data

Published electrophysiology measurements (homomeric).
PubMed ID Cell Type S.S Peak (%WT) Peak Tail IKr (%WT) V1/2 Act. V1/2 Inact. Recov. Inact. Deactivation (%WT)
21109023 CHO 0 10.0 59.4 None 0.7239819

Heteromeric channel data

Published electrophysiology measurements (heteromeric).
PubMed ID Cell Type S.S Peak (%WT) Peak Tail IKr (%WT) V1/2 Act. V1/2 Inact. Deactivation (%WT)
21109023 CHO 100 0 8.8 -31.5 1.076923077

Nearby variants

Neighbouring residues within 15 Ångström provide structural context. Variants listed in the right-most column have been observed clinically or in gnomAD. Note that 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 15Å window.

Previously observed variants near E637G.
Neighbour residue Distance (Å) Observed variants
637 0 E637K, E637G, E637X,
634 4 T634P, T634A, T634S, T634S, T634I,
636 4
632 5 P632A, P632S,
638 5 K638E, K638D, K638Del, K638R,
633 6 N633D, N633S, N633I,
568 6 W568C, W568C,
571 6 I571L, I571V,
635 7 N635I,
640 7 F640L, F640V, F640Del, F640L, F640L,
585 7 W585C, W585C,
584 7 G584S, G584R, G584C,
639 7 I639F, I639N,
631 7 S631F,
641 8 S641P, S641F,
572 8 G572S, G572R, G572C, G572D,
575 9 E575K,
616 9 Y616S,
617 9 F617L, F617V, F617L, F617L,
630 10 V630I, V630T, V630A,
583 10 I583V,
570 10
586 10 L586M,
629 10 N629D, N629T, N629S, N629I, N629K, N629K,
642 10 I642V, I642Del,
612 10 V612L, V612L, V612A,
567 11 I567T, I567M,
627 11 F627L, F627fsX, F627X, F627L, F627L,
613 11 T613A, T613L, T613K, T613M,
588 11 N588D, N588K, N588K,
573 11
644 11 V644I, V644F,
593 11 I593V, I593K, I593T, I593R, I593X,
569 12 Y569H, Y569C, Y569X,
643 12
614 12 A614T, A614V,
609 12 D609N, D609G,
592 12 Q592X,
587 12
565 12
618 12 T618S, T618S,
574 12 M574L, M574V, M574L,
564 12 L564L,
621 12 S621R, S621N, S621R, S621R,
576 12
645 13 M645L, M645V, M645L, M645R, M645I, M645I, M645I
613 13 T613A, T613L, T613K, T613M,
608 13
628 13 G628S, G628R, G628Del, G628D, G628A, G628V,
589 13 L589P,
628 13 G628S, G628R, G628Del, G628D, G628A, G628V,
577 13
630 13 V630I, V630T, V630A,
589 14 L589P,
615 14 L615V, L615F,
566 14 C566S, C566R, C566G, C566S, C566F,
620 14 S620G, S620I,
614 14 A614T, A614V,
629 14 N629D, N629T, N629S, N629I, N629K, N629K,
620 14 S620G, S620I,
616 15 Y616S,
610 15
626 15 G626S, G626A, G626V,
626 15 G626S, G626A, G626V,
619 15