KCNH2 Variant F805C

Summary of observed carriers, functional annotations, and structural context for KCNH2 F805C. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT2 penetrance

53%

10/19 effective observations

Total carriers

9

7 LQT2 · 2 unaffected

Functional studies

5

Publications with functional data

F805C 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 5%. 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 (%)
-7.381 1.0 -3 0.978 76

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
11854117 2002 11 0 11
11844290 2002 7 2 5
10973849 2000 1 0 1
15840476 2005 1 0 1
Literature, cohort, and gnomAD 9 2 7
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)
11741928 HEK293 0 None None None None
12837749 HEK293 19 None None None None
15851652 HEK293 None None None None
15961404 HEK293 0 None None None None
16432067 HEK293 5 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)
11741928 HEK293 None None None
12837749 HEK293 None None None
15851652 HEK293 None None None
15961404 HEK293 None None None
16432067 HEK293 60 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 F805C.
Neighbour residue Distance (Å) Observed variants
805 0 F805S, F805C,
780 4
806 5 G806R, G806R,
804 5
779 6
859 7 T859M, T859R,
860 7
781 7
799 7 L799sp,
782 7 I782fsX, I782N,
803 7 D803Y, D803X,
858 8 I858V, I858T,
862 8 L862P,
778 8 A778T,
787 8
822 8 V822M, V822L, V822L,
789 9
770 9
769 9
830 9
776 9 L776I, L776P,
807 9 E807X,
861 9 N861H, N861I,
832 10
800 10
797 10 A797T,
831 10
833 10
820 11 G820R, G820R,
808 11
777 11
818 11 S818A, S818W, S818L,
788 11 E788K, E788D, E788D,
802 12
761 12
798 12 I798fsX,
819 12 N819K, N819K,
783 12 S783P,
821 12 D821E, D821E,
828 12
56 12 R56Q,
786 12
824 12
856 12
857 12 E857X,
57 12 A57P,
60 13 M60T,
785 13 G785S, G785fsX, G785D,
790 13
763 13
796 13 V796L, V796L, V796Del,
823 13 R823W, R823fsX, R823T, R823Q,
834 13 H834R,
768 13
771 13 H771fsX, H771R,
801 13 K801T,
774 13 D774Y, D774X,
829 13 D829A, D829E, D829E,
736 13
816 13 G816V,
809 13
758 13
835 14 R835W, R835fsX, R835Q,
61 14 Q61R,
759 14 K759N, K759N,
772 14
775 14
740 14 C740G, C740W,
767 14 D767X,
42 14 I42N,
760 14
825 14
838 15 L838R,
853 15 W853X,
791 15 R791W, R791Q,
44 15 C44F, C44X, C44W,
773 15
863 15 R863X, R863P
43 15 Y43D, Y43C,
762 15
723 15 C723R, C723G, C723X,