KCNH2 Variant L1066M Detail

We estimate the penetrance of LQTS for KCNH2 L1066M is 9%. We are unaware of any observations of this variant in individuals. L1066M is not present in gnomAD. We have tested the trafficking efficiency of this variant, 75% of WT with a standard error of 13%; 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. L1066M 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 L1066M around 9% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.507 0.998 1 0.76 2
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.

L1066M 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
1066 0
1065 4
1067 4
1064 5 L1064X,
1068 5 Q1068R, Q1068X,
1063 7 V1063I, V1063L,
1069 7 R1069S, R1069S,
1062 8 T1062I, T1062P, T1062X,
1070 8 Q1070P, Q1070X,
1061 8 A1061P,
1071 8 M1071V,
1060 9 M1060V, M1060I, M1060I, M1060I,
1072 9 T1072S, T1072M,
1059 10 D1059E, D1059E,
1073 10 L1073P,
1058 11 A1058T, A1058E,
1074 11
1057 11 S1057fsX, S1057N,
1075 11 P1075L,
1056 12 L1056fsX,
1076 12
1055 13 R1055Q, R1055W,
1077 13 A1077D, A1077T,
1054 13 T1054fsX,
1078 13 Y1078C,
1053 14 E1053fsX, E1053X,
1079 14 S1079N,
1052 14
1080 14
1051 15
1081 15