KCNH2 Variant G546V

Summary of observed carriers, functional annotations, and structural context for KCNH2 G546V. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT2 penetrance

12%

1/10 effective observations

Total carriers

0

0 LQT2 · 0 unaffected

Functional studies

1

Publications with functional data

G546V has not been reported in gnomAD. This residue resides in a Non_Hotspot region for LQT2.

We have tested the trafficking efficiency of this variant: 56% of WT with a standard error of 18%. 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 1 individuals with LQT2 and 9 unaffected individuals.

In silico predictors

Variant-level computational predictors.
PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density LQT2 (%)
-8.626 0.999 -3 0.943 8

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 9 1

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)
21044581 Xeno -46.1 None 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)
21044581 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 G546V.
Neighbour residue Distance (Å) Observed variants
546 0
547 3 A547T,
548 5
549 5 V549M,
545 6
666 6
662 7
665 7 R665Q,
550 7
543 7 S543fsX,
544 8 E544fsX, E544A,
663 9
674 10 H674fsX, H674Y,
678 10
551 10 F551L, F551L, F551L,
552 10 L552S,
667 10 Y667X,
659 10
661 11 A661V,
553 11 L553V,
681 11 R681W,
542 11
658 12
675 12
668 12 S668L,
664 12 Q664X,
540 12 D540fsX,
677 12 M677T,
412 12 W412X,
539 13
660 13 S660L,
554 13
682 13 E682X,
671 13 A671Del, A671G,
541 13 R541C, R541H,
685 14 R685C, R685H, R685P,
673 14
555 14
657 14 G657S, G657V,
669 14 G669X, G669R, G669C,
670 14
655 15