KCNH2 Variant G914R Detail

We estimate the penetrance of LQTS for KCNH2 G914R is 8%. This variant was found in a total of 1 carriers in 0 papers or gnomAD (version 4), 0 had LQTS. G914R is present in 1 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 90% 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. G914R 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 G914R around 8% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-0.512 0.014 -1 0.485 7
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.

G914R 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
914 0
913 4 A913V,
915 4 A915X, A915V, A915fsX,
912 5 R912X, R912Q, R912W,
916 5
911 7 G911X,
917 7 P917L,
910 8 P910fsX, P910L,
918 8
909 8 G909X,
919 8
908 9 L908fsX, L908X,
920 9 R920G, R920fsX, R920W, R920Q,
907 10 A907X,
921 10
906 11 S906L,
922 11 R922fsX, R922Q, R922W,
905 11 V905M,
923 11 P923Q, P923L, P923fsX, P923X,
904 12 E904X,
924 12 G924V, G924A, G924X, G924E, G924W,
903 13 G903R, G903R,
925 13 G925R, G925A, G925E, G925X, G925fsX, G925R, G925V,
902 13
926 13 P926S, P926fsX, P926L, P926X,
901 14 Q901fsX,
927 14 W927X, W927S, W927L, W927C, W927C, W927G,
900 14 E900X,
928 14 G928E, G928fsX,
899 15 T899X, T899M,
929 15