KCNH2 Variant E1118K Detail

We estimate the penetrance of LQTS for KCNH2 E1118K is 8%. We are unaware of any observations of this variant in individuals. E1118K is not present in gnomAD. We have tested the trafficking efficiency of this variant, 55% of WT with a standard error of 21%; 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. E1118K has not been functionally characterized. This residue is located in a Non_Hotspot region for LQT2. In silico predictions, functional data (if available), and location in structure are equivalent to observing 0 individuals with LQT2 and 10 unaffected individuals.These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 E1118K around 8% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-0.983 0.956 0 0.541 3
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
LITERATURE, COHORT, AND GNOMAD: - 0 0 0 -
VARIANT FEATURES ALONE: - 10 10 0 -
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.

E1118K has 31 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
1118 0
1117 4 C1117fsX,
1119 4 E1119V, E1119Q,
1116 5 A1116V,
1120 5
1115 7 M1115T,
1121 7
1114 8
1122 8 P1122R, P1122fsX, P1122L,
1113 8
1123 8 G1123R, G1123R,
1112 9
1124 9
1111 10 V1111F,
1125 10 P1125X, P1125A,
1110 11 Q1110P,
1126 11 E1126fsX,
1109 11
1127 11
1108 12 L1108V,
1128 12
1107 13 S1107L,
1129 13
1106 13
1130 13
1105 14 L1105S,
1131 14 G1131V,
1104 14 T1104I,
1132 14 P1132A,
1103 15 L1103P,
1133 15