KCNH2 Variant T1054A Detail

We estimate the penetrance of LQTS for KCNH2 T1054A is 9%. We are unaware of any observations of this variant in individuals. T1054A is not present in gnomAD. We have tested the trafficking efficiency of this variant, 74% of WT with a standard error of 7%; 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. T1054A 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 T1054A around 9% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.617 0.478 -1 0.558 1
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.

T1054A 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
1054 0 T1054fsX,
1053 4 E1053fsX, E1053X,
1055 4 R1055W, R1055Q,
1052 5
1056 5 L1056fsX,
1051 7
1057 7 S1057N, S1057fsX,
1050 8
1058 8 A1058T, A1058E,
1049 8
1059 8 D1059E, D1059E,
1048 9
1060 9 M1060V, M1060I, M1060I, M1060I,
1047 10 R1047H, R1047C, R1047L,
1061 10 A1061P,
1046 11 Q1046X,
1062 11 T1062X, T1062P, T1062I,
1045 11 L1045F,
1063 11 V1063L, V1063I,
1044 12
1064 12 L1064X,
1043 13 D1043G,
1065 13
1042 13
1066 13
1041 14
1067 14
1040 14
1068 14 Q1068R, Q1068X,
1039 15 E1039X,
1069 15 R1069S, R1069S,