KCNH2 Variant T13N Detail

We estimate the penetrance of LQTS for KCNH2 T13N is 6%. This variant was found in a total of 25 carriers in 1 papers or gnomAD, 1 had LQTS. T13N is present in 21 alleles in gnomAD. T13N 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 1 individuals with LQT2 and 9 unaffected individuals.These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 T13N around 6% (2/35).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-2.764 0.135 -1 0.897 9
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
France Cohort 2020 4 3 1
LITERATURE, COHORT, AND GNOMAD: - 25 24 1 -
VARIANT FEATURES ALONE: - 10 9 1 -
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.

T13N has 55 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
13 0 T13N,
10 5
14 5
12 5 N12D,
825 6
16 6 D16A,
15 6 L15V,
9 6 A9T, A9V,
17 7
11 7 Q11H, Q11L, Q11H,
826 9 T826I, T826A,
788 9 E788K, E788D, E788D,
18 9 I18M,
786 9
824 10
765 10
8 10
19 10 I19F,
766 11
20 11 R20G, R20L,
798 11 I798fsX,
7 12
795 12 V795I,
823 12 R823W, R823fsX, R823T, R823Q,
480 12 E480V,
787 12
482 12 V482A,
785 12 G785S, G785D, G785fsX,
481 12
827 12
124 12 M124T, M124R,
828 13
123 13
21 13
797 13 A797T,
115 13 V115M,
479 13
764 13
790 14
31 14 I31S,
117 14
767 14 D767X,
43 14 Y43D, Y43C,
42 14 I42N,
483 14 V483I,
799 14 L799sp,
800 14
789 14
6 15 G6R,
763 15
488 15 R488C, R488H,
793 15 D793N,
484 15
22 15 F22Y, F22S,
794 15 V794I, V794D,