KCNQ1 Variant G460V Detail

We estimate the penetrance of LQTS for KCNQ1 G460V is 10%. We are unaware of any observations of this variant in individuals. G460V is not present in gnomAD. G460V 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 G460V around 10% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.76 0.02 -1 0.587 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.

G460V 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
460 0 G460S, G460D, G460C,
459 4 D459N, D459V,
461 4
458 5
462 5
457 7
463 7 S463T,
456 8 F456L, F456L, F456L,
464 8 S464P,
455 8 H455Y, H455Q, H455Q, H455R,
465 8
454 9
466 9
453 10
467 10 K467R,
452 11 R452Q, R452W, R452L,
468 11 S468G, S468N,
451 11 R451Q, R451W,
469 11
450 12 E450K,
470 12
449 13 E449K,
471 13
448 13 P448R, P448Q, P448L, P448S,
472 13 L472P,
447 14 P447H,
473 14 E473Q,
446 14 D446E, D446E, D446E, D446E, D446N,
474 14
445 15
475 15