KCNH2 Variant T1102I Detail

We estimate the penetrance of LQTS for KCNH2 T1102I is 8%. This variant was found in a total of 1 carriers in 0 papers or gnomAD (version 4), 0 had LQTS. T1102I is present in 1 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 81% of WT with a standard error of 8%; 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. T1102I 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 T1102I around 8% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.811 0.0 -1 0.59 0
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: - 1 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.

T1102I 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
1102 0
1101 4 P1101fsX,
1103 4 L1103P,
1100 5
1104 5 T1104I,
1099 7 P1099L,
1105 7 L1105S,
1098 8 S1098R, S1098R, S1098R,
1106 8
1097 8 V1097I,
1107 8 S1107L,
1096 9
1108 9 L1108V,
1095 10
1109 10
1094 11 L1094M,
1110 11 Q1110P,
1093 11 P1093R, P1093L,
1111 11 V1111F,
1092 12 S1092F,
1112 12
1091 13
1113 13
1090 13 S1090F,
1114 13
1089 14 T1089A, T1089I,
1115 14 M1115T,
1088 14
1116 14 A1116V,
1087 15 G1087X,
1117 15 C1117fsX,