KCNH2 Variant E518A

Summary of observed carriers, functional annotations, and structural context for KCNH2 E518A. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT2 penetrance

10%

0/10 effective observations

Total carriers

0

0 LQT2 · 0 unaffected

Functional studies

2

Publications with functional data

E518A has not been reported in gnomAD. This residue resides in a Mild_Hotspot region for LQT2.

We have tested the trafficking efficiency of this variant: 135% of WT with a standard error of 43%. 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 0 individuals with LQT2 and 10 unaffected individuals.

In silico predictors

Variant-level computational predictors.
PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density LQT2 (%)
-3.746 0.001 -1 0.768 13

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
Literature, cohort, and gnomAD 0 0 0
Variant features alone 10 10 0

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)
15528201 Xeno 20.2 -1.6 None None
15975984 Xeno 26.3 5.2 None None

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)
15528201 Xeno None None None
15975984 Xeno None None None

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 E518A.
Neighbour residue Distance (Å) Observed variants
518 0
517 4
519 4
516 5
520 5
515 7
521 7
514 8 G514S,
522 8 G522E,
513 8
523 8
512 9
524 9
511 10
525 10 K525N, K525N,
510 11
526 11
509 11 D509N,
527 11
508 12
528 12 R528W, R528X, R528P,
507 13 P507S, P507L,
529 13
506 13 I506V,
530 13
505 14 A505V,
531 14 R531W, R531Del, R531Q
504 14 A504V,
532 14
503 15
533 15