KCNQ1 Variant L497P Detail

We estimate the penetrance of LQTS for KCNQ1 L497P is 9%. This variant was found in a total of 1 carriers in 0 papers or gnomAD, 0 had LQTS. L497P is present in 1 alleles in gnomAD. L497P 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 0 individuals with LQT1 and 10 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 L497P around 9% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.32 0.99 3 0.646 0
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
LITERATURE, COHORT, AND GNOMAD: - 1 1 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.

L497P 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
497 0 L497P,
496 4
498 4
495 5 T495S, T495S, T495A,
499 5 P499S,
494 7
500 7 I500L, I500V,
493 8 G493A,
501 8 T501A,
492 8 L492ins,
502 8
491 9
503 9
490 10
504 10
489 11
505 11 Q505R,
488 11 D488E, D488E,
506 11
487 12 E487K,
507 12 R507Q, R507W,
486 13 A486T,
508 13 E508G,
485 13 F485S,
509 13 H509Q, H509Q, H509R,
484 14
510 14 H510R, H510Y,
483 14
511 14 R511Q, R511W,
482 15 T482N, T482A, T482S, T482S,
512 15