KCNH2 Variant I500Del

Summary of observed carriers, functional annotations, and structural context for KCNH2 I500Del. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT2 penetrance

54%

90% CI: 33.5% – 74.6%

8/15 effective observations

Total carriers

5

5 LQT2 · 0 unaffected

Functional studies

1

Publications with functional data

I500Del has not been reported in gnomAD. This residue resides in a Hotspot region for LQT2.

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 (%)
None None None None 80

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
7889573 1995 11 0 5
Literature, cohort, and gnomAD 5 0 5
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)
8700910 Xeno 0 None 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)
8700910 Xeno 51 3.0 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 I500Del.
Neighbour residue Distance (Å) Observed variants
500 0 I500Del,
499 4
501 5 D501N, D501H, D501Y,
530 6
503 6
502 6 M502I, M502I, M502I,
497 7 W497L, W497X,
533 7
498 7
504 8 A504V,
496 8
534 8 R534C,
527 9
531 10 R531W, R531Del, R531Q,
537 10 R537W
505 10 A505V,
493 10 Y493H, Y493C, Y493F, Y493Ins,
532 10
529 11
506 11 I506V,
467 11
495 11 K495X,
536 12 A536X,
463 12 F463L, F463L, F463L,
494 12 F494Del,
535 13 V535M,
466 13 D466E, D466E,
528 13 R528W, R528X, R528P,
470 13 N470D,
526 13
538 13
464 14 I464X,
418 14
492 14 H492Y,
421 15 T421fsX, T421M,
471 15 F471X,
507 15 P507S, P507L,