KCNH2 Variant T443S Detail

We estimate the penetrance of LQTS for KCNH2 T443S is 14%. We are unaware of any observations of this variant in individuals. T443S is not present in gnomAD. T443S 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 1 individuals with LQT2 and 9 unaffected individuals.These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 T443S around 14% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-0.523 0.0 0 0.607 15
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
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.

T443S 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
443 0 T443fsX, T443N,
442 4
444 4 E444D, E444K, E444D,
441 5 P441R, P441L,
445 5
440 7 P440L,
446 7
439 8
447 8 Y447X,
438 8 E438X, E438K,
448 8 A448S, A448T,
437 9
449 9
436 10 T436M,
450 10
435 11 E435X, E435G,
451 11 P451L,
434 11
452 11
433 12
453 12
432 13
454 13
431 13 F431L, F431L, F431L,
455 13
430 14
456 14 D456Y,
429 14 A429V, A429P,
457 14 L457P,
428 15 S428L, S428X, S428fsX,
458 15