KCNQ1 Variant C445W Detail

We estimate the penetrance of LQTS for KCNQ1 C445W is 11%. We are unaware of any observations of this variant in individuals. C445W is not present in gnomAD. C445W has not been functionally characterized. This residue is located in a Non_Hotspot region for LQT1. In silico predictions, functional data (if available), and location in structure are equivalent to observing 1 individuals with LQT1 and 9 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 C445W around 11% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-0.98 0.575 -3 0.6 4
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 LQT1 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.

C445W 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. This results from the fact that the functional KV7.1 channel 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
445 0
444 4 T444M, T444K,
446 4 D446E, D446E, D446E, D446E, D446N,
443 5
447 5 P447H,
442 7 H442R,
448 7 P448R, P448Q, P448L, P448S,
441 8 P441S,
449 8 E449K,
440 8
450 8 E450K,
439 9
451 9 R451Q, R451W,
438 10
452 10 R452Q, R452W, R452L,
437 11 M437V,
453 11
436 11
454 11
435 12
455 12 H455Y, H455Q, H455Q, H455R,
434 13 G434R, G434R,
456 13 F456L, F456L, F456L,
433 13 P433A,
457 13
432 14 T432I, T432A,
458 14
431 14 V431L, V431L,
459 14 D459N, D459V,
430 15
460 15 G460S, G460D, G460C,