KCNH2 Variant D16H Detail

We estimate the penetrance of LQTS for KCNH2 D16H is 10%. We are unaware of any observations of this variant in individuals. D16H is not present in gnomAD. We have tested the trafficking efficiency of this variant, 111% of WT with a standard error of 17%; 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. D16H 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 D16H around 10% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-2.986 0.0 -1 0.794 24
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: - 0 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.

D16H has 58 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
16 0 D16A,
17 4
19 5 I19F,
15 6 L15V,
20 6 R20L, R20G,
13 6 T13N,
786 6
18 7 I18M,
825 7
826 8 T826A, T826I,
14 8
785 8 G785fsX, G785D, G785S,
798 9 I798fsX,
12 9 N12D,
21 10
788 10 E788K, E788D, E788D,
43 10 Y43C, Y43D,
10 10
800 10
23 10
787 11
22 11 F22Y, F22S,
824 11
828 11
9 11 A9T, A9V,
801 11 K801T,
799 12 L799sp,
31 12 I31S,
765 12
827 12
29 12 F29L, F29L, F29L, F29S, F29V,
797 12 A797T,
11 13 Q11L, Q11H, Q11H,
42 13 I42N,
24 13
479 13
784 13 R784W, R784G, R784Q,
480 13 E480V,
795 13 V795I,
124 13 M124T, M124R,
45 13 N45D, N45K, N45K,
126 14
44 14 C44W, C44X, C44F,
766 14
25 14 Q25P,
115 14 V115M,
823 14 R823W, R823fsX, R823Q, R823T,
782 14 I782fsX, I782N,
764 14
829 14 D829E, D829A, D829E,
763 14
27 15 R27P, R27X,
789 15
783 15 S783P,
30 15 I30T, I30Del,
803 15 D803Y, D803X,
8 15
481 15