KCNQ1 Variant S504L Detail

We estimate the penetrance of LQTS for KCNQ1 S504L is 10%. We are unaware of any observations of this variant in individuals. S504L is not present in gnomAD. S504L 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 S504L around 10% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-2.19 0.392 -3 0.729 3
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: - 0 0 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.

S504L 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
504 0
503 4
505 4 Q505R,
502 5
506 5
501 7 T501A,
507 7 R507Q, R507W,
500 8 I500L, I500V,
508 8 E508G,
499 8 P499S,
509 8 H509Q, H509Q, H509R,
498 9
510 9 H510R, H510Y,
497 10 L497P,
511 10 R511Q, R511W,
496 11
512 11
495 11 T495S, T495S, T495A,
513 11 T513A, T513S, T513S,
494 12
514 12 I514T,
493 13 G493A,
515 13
492 13 L492ins,
516 13
491 14
517 14 I517T,
490 14
518 14 R518Q, R518G,
489 15
519 15 R519H, R519C,