KCNH2 Variant P963T Detail

We estimate the penetrance of LQTS for KCNH2 P963T is 4%. This variant was found in a total of 10 carriers in 1 papers or gnomAD (version 4), 0 had LQTS. P963T is present in 8 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 117% of WT with a standard error of 18%; 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. P963T has been functionally characterized in 1 papers. 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 P963T around 4% (0/20).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.323 0.001 1 0.541 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
29331839 2018 4 2 2 children with SIDS
LITERATURE, COHORT, AND GNOMAD: - 10 2 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.

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)
31493599 HEK293 100 100 0.0 0.0 None None

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)
31493599 HEK293 100 100 None None None

P963T 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
963 0 P963T,
962 4
964 4 G964X,
961 5 P961X,
965 5 G965R, G965X, G965R, G965fsX,
960 7 S960N,
966 7 E966K, E966A,
959 8
967 8 P967X, P967L,
958 8 F958L, F958L, F958L,
968 8 P968A, P968L, P968fsX,
957 9
969 9 G969D, G969X,
956 10
970 10 G970A,
955 11 L955V,
971 11
954 11 R954C, R954H,
972 11 P972H, P972S,
953 12
973 12 L973X,
952 13 P952T, P952S,
974 13 M974L, M974L,
951 13
975 13
950 14
976 14
949 14 S949R, S949R, S949R,
977 14 C977S, C977S, C977Y, C977F, C977W,
948 15 R948H, R948C, R948S,
978 15 E978K, E978X,