KCNH2 Variant S735L Detail

We estimate the penetrance of LQTS for KCNH2 S735L is 8%. This variant was found in a total of 3 carriers in 1 papers or gnomAD (version 4), 0 had LQTS. S735L is present in 1 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 70% 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. S735L has not been functionally characterized. This residue is located in a Mild_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 S735L around 8% (0/13).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-3.61 0.249 -2 0.617 11
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
16379539 2005 2 2
LITERATURE, COHORT, AND GNOMAD: - 3 3 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.

S735L has 49 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
735 0 S735L,
736 4
734 5 R734H, R734C,
739 6 H739fsX,
733 6
738 6 Q738X,
737 6 L737P,
783 7 S783P,
740 7 C740G, C740W,
831 8
802 8
732 9
784 9 R784Q, R784W, R784G,
781 9
731 9 H731R,
782 9 I782N, I782fsX,
730 10
743 10
829 10 D829A, D829E, D829E,
801 10 K801T,
758 11
830 11
744 11 R744X, R744P, R744G, R744fsX, R744Q,
760 11
729 12
755 12
803 12 D803Y, D803X,
751 12 L751V,
742 12
741 12 K741R,
804 13
785 13 G785D, G785S, G785fsX,
800 13
687 13
754 13
761 13
688 14
762 14
728 14
828 14
759 14 K759N, K759N,
832 14
727 14
833 14
780 14
690 15
779 15
689 15
726 15