KCNQ1 Variant Q531K Detail

We estimate the penetrance of LQTS for KCNQ1 Q531K is 34%. We are unaware of any observations of this variant in individuals. Q531K is not present in gnomAD. Q531K has not been functionally characterized. This residue is located in a Mild_Hotspot region for LQT1. In silico predictions, functional data (if available), and location in structure are equivalent to observing 3 individuals with LQT1 and 7 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 Q531K around 34% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-2.79 0.1 0 0.786 35
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 7 3 -
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.

Q531K has 24 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
530 6
527 6
528 7
533 8 R533W, R533Q,
529 8
370 10 A370V,
526 10 K526Q, K526E,
525 10 A525T, A525V,
524 11 V524G,
371 12 A371T,
369 12
360 13 R360ins, R360G, R360M,
547 13 Q547R,
362 13 K362R, K362del,
374 13 L374H, L374F,
373 14 S373P,
366 14 R366W, R366Q,
368 14
535 14
523 15
361 15
372 15
363 15 H363N,
522 15 Y522S,