KCNH2 Variant L799sp Detail

We estimate the penetrance of LQTS for KCNH2 L799sp is 57%. This variant was found in a total of 5 carriers in 4 papers or gnomAD, 5 had LQTS. L799sp is not present in gnomAD. L799sp has not been functionally characterized. This residue is located in a None region for LQT2. In silico predictions, functional data (if available), and location in structure are equivalent to observing 3 individuals with LQT2 and 7 unaffected individuals.These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 L799sp around 57% (8/15).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
None None None None
PROVEAN scores less than -2 are considered deleterious. REVEL scores higher than 0.5 or 0.75 are considered likely pathogenic (higher sensitivity with the former cutoff, higher specificity with the latter cutoff). A PolyPhen-2 score of 0.85 or greater is considered likely pathogenic. BLAST-PSSM reflects the evolutionary conservation of residue substitutions, more negative numbers indicate fewer observations of the specific substitution than is expected. Penetrance density is our previously published method to calculate the average LQTS probability density in a shell of residues surrounding a residue of interest (Kroncke et al. 2019).

Reported Carrier Data

PubMed ID Year Carriers Unaffected LQT2 Other Disease
11854117 2002 5 0 5
10973849 2000 1 0 1
15840476 2005 3 0 3
15840476 2005 1 0 1
LITERATURE, COHORT, AND GNOMAD: - 5 0 5 -
VARIANT FEATURES ALONE: - 10 7 3 -
Summary totals might not agree with the literature table because of duplicate patients, which were excluded from the total counts. We do not distinguish here between multiple missense codons. Missense variants are combined across degenerate codon substitutions since codon-level data were not consistently available for curation.

L799sp has 78 previously observed neighbors within 15 angstroms

A residue within a folded protein on average has nearest neighbors that fall roughly into two shells: a "nearest" neighbor around 5-6 angstroms and a second shell around 11 angstroms. NOTE: 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 15A window. All variants shown in the rightmost column have been observed in at least one individual in the literature or gnomAD.

Neighbor Distance (Angstroms) Variants Observed in Individuals
799 0 L799sp,
800 4
787 5
798 5 I798fsX,
803 5 D803X, D803Y,
797 6 A797T,
786 7
782 7 I782fsX, I782N,
859 7 T859R, T859M,
788 7 E788K, E788D, E788D,
789 7
805 7 F805C, F805S,
860 8
56 8 R56Q,
43 8 Y43D, Y43C,
785 8 G785S, G785D, G785fsX,
804 8
801 9 K801T,
42 9 I42N,
44 9 C44F, C44W, C44X,
60 9 M60T,
802 9
822 9 V822L, V822L, V822M,
796 10 V796L, V796L, V796Del,
824 10
828 10
825 10
783 10 S783P,
780 11
830 11
858 11 I858V, I858T,
781 11
795 11 V795I,
806 11 G806R, G806R,
790 11
826 11 T826I, T826A,
57 11 A57P,
16 12 D16A,
19 12 I19F,
15 12 L15V,
41 12 V41A,
823 12 R823W, R823fsX, R823T, R823Q,
31 12 I31S,
45 12 N45K, N45D, N45K,
61 12 Q61R,
769 12
862 12 L862P,
829 12 D829E, D829E, D829A,
46 13 D46E, D46E, D46Y,
763 13
59 13
784 13 R784Q, R784G, R784W,
820 13 G820R, G820R,
861 13 N861I, N861H,
770 13
55 13 S55L,
779 13
821 13 D821E, D821E,
12 13 N12D,
831 13
857 13 E857X,
30 14 I30Del, I30T,
40 14
29 14 F29L, F29V, F29S, F29L, F29L,
819 14 N819K, N819K,
13 14 T13N,
32 14 A32T,
767 14 D767X,
49 15 C49R, C49G,
794 15 V794I, V794D,
768 15
761 15
766 15
791 15 R791Q, R791W,
765 15
740 15 C740G, C740W,
764 15
736 15