KCNH2 Variant E58D Detail

We estimate the penetrance of LQTS for KCNH2 E58D is 22%. This variant was found in a total of 1 carriers in 1 papers or gnomAD (version 4), 1 had LQTS. E58D is not present in gnomAD. We have tested the trafficking efficiency of this variant, 70% of WT with a standard error of 20%; 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. E58D has been functionally characterized in 1 papers. This residue is located in a Hotspot region for LQT2. In silico predictions, functional data (if available), and location in structure are equivalent to observing 2 individuals with LQT2 and 8 unaffected individuals.These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 E58D around 22% (3/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-0.667 0.0 4 0.659 80
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
Italy Cohort 2020 1 0 1
LITERATURE, COHORT, AND GNOMAD: - 1 0 1 -
VARIANT FEATURES ALONE: - 10 8 2 -
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.

Functional Data Homozygously Collected

Steady state (S.S.) and peak tail current are relative % to wildtype (100% being no different from wildtype). V0.5 act/inact are the voltages at which half of the maximal current is reached during an activation and inactivation protocol, each is in units of mV and relative to wildtype. Recovery from inactivation (Rec. inact.) and deactivation time (Deactivation) are the ratio of characteristic time constants with wildtype (unitless).

PubMed ID Cell Type S.S Peak (%WT) Peak Tail IKr (%WT) V1/2 Act. V1/2 Inact. Recov. Inact. Deactivation (%WT)
25417810 HEK293 64 -0.5 None None 0.893413174

Functional Data Heterozygously Collected

Functional parameters are the same as defined above.

PubMed ID Cell Type S.S Peak (%WT) Peak Tail IKr (%WT) V1/2 Act. V1/2 Inact. Deactivation (%WT)
25417810 HEK293 None None None

E58D has 44 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
58 0 E58K, E58D, E58D,
57 4 A57P,
55 4 S55L,
54 5 Y54N, Y54X,
59 5
62 7 R62Q,
60 8 M60T,
68 8 F68L, F68L, F68L, F68V,
857 8 E857X,
53 8 G53S, G53R,
101 9 K101E,
56 9 R56Q,
52 10 C52W,
49 10 C49G, C49R,
61 10 Q61R,
859 10 T859R, T859M,
44 10 C44W, C44F, C44X,
858 11 I858V, I858T,
48 11
41 11 V41A,
69 11 L69Del, L69P,
66 12 C66Y, C66G, C66R,
860 12
63 12 P63H,
861 12 N861H, N861I,
67 13
856 13
855 14 S855R, S855R, S855R,
854 14
804 14
40 14
51 14
102 14 D102X, D102H, D102V,
30 14 I30Del, I30T,
100 14 R100G, R100Q, R100P,
45 14 N45K, N45D, N45K,
46 14 D46Y, D46E, D46E,
43 14 Y43C, Y43D,
803 14 D803X, D803Y,
741 14 K741R,
42 14 I42N,
50 14 E50X,
47 15 G47V, G47C,
64 15 C64R, C64Y,