KCNH2 Variant L1023Del Detail

We estimate the penetrance of LQTS for KCNH2 L1023Del is 6%. This variant was found in a total of 4 carriers in 1 papers or gnomAD (version 4), 0 had LQTS. L1023Del is present in 3 alleles in gnomAD. L1023Del 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 L1023Del around 6% (0/14).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
None None None None 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
14661677 2003 1 1
LITERATURE, COHORT, AND GNOMAD: - 4 1 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.

L1023Del 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
1023 0 L1023P, L1023Del,
1022 4
1024 4
1021 5 S1021N, S1021fsX,
1025 5
1020 7
1026 7 P1026R,
1019 8
1027 8 L1027I,
1018 8 P1018A, P1018L,
1028 8 S1028Del,
1017 9 A1017S, A1017V, A1017T, A1017fsX,
1029 9 S1029fsX,
1016 10
1030 10 P1030L, P1030X,
1015 11 C1015Y,
1031 11 G1031X, G1031C, G1031fsX,
1014 11 R1014X, R1014fsX,
1032 11 R1032W, R1032P, R1032fsX, R1032X, R1032Q,
1013 12
1033 12 R1033fsX, R1033Q, R1033X, R1033W,
1012 13 L1012fsX,
1034 13 P1034X, P1034fsX,
1011 13 E1011K,
1035 13 R1035W, R1035X, R1035Q, R1035fsX,
1010 14
1036 14 G1036X, G1036Del, G1036D, G1036fsX,
1009 14 Y1009X,
1037 14 D1037E, D1037N, D1037X, D1037E, D1037fsX,
1008 15
1038 15 V1038M, V1038L, V1038X, V1038fsX, V1038L,