KCNQ1 Variant R366Q Detail

We estimate the penetrance of LQTS for KCNQ1 R366Q is 69%. This variant was found in a total of 13 carriers in 9 papers or gnomAD, 8 had LQTS. R366Q is present in 1 alleles in gnomAD. R366Q has been functionally characterized in 1 papers. This residue is located in a Hotspot region for LQT1. In silico predictions, functional data (if available), and location in structure are equivalent to observing 7 individuals with LQT1 and 3 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 R366Q around 69% (15/23).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-3.61 1.0 1 0.969 83
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
32893267 2020 7 None 7 None
30758498 2019 2 None None None
29037160 2017 4 4 None None
24689698 2015 2 2 None None
24667783 2015 1 None 1 None
24363352 2014 1 None None None
19934648 2010 None None None None
19716085 2009 1 None 1 None
14678125 2003 2 None 2 None
LITERATURE, COHORT, AND GNOMAD: - 13 5 8
VARIANT FEATURES ALONE: - 10 3 7 -
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.

Functional Data Homozygously Collected

Peak current is relative to wildtype (100% being no different from wildtype). V0.5 activation is the voltages at which half of the maximal current is reached during an activation in units of mV and relative to wildtype. Recovery from inactivation (Rec. inact.) and deactivation time (Deactivation) are the ratio of characteristic time constants with wildtype (unitless).

PubMed ID Cell Type Peak Current IKs (%WT) V1/2 Act. Activation time (%WT) Deactivation time (%WT)
19934648 Oocytes 22 29.0 1.0 None

Functional Data Heterozygously Collected

Functional parameters are the same as defined above.

PubMed ID Cell Type Peak Current IKs (%WT) V1/2 Act. Activation time (%WT) Deactivation time (%WT)
19934648 Oocytes None None None

R366Q has 22 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
363 5 H363N,
365 6 N365H,
364 8 F364L, F364L, F364L, F364S,
366 8 R366W, R366Q,
368 9
369 9
362 11 K362R, K362del,
532 12
531 12
371 12 A371T,
540 12
534 13
535 14
543 14 E543K,
528 14
372 14
544 14 Q544E,
361 14
373 15 S373P,
527 15
530 15
533 15 R533W, R533Q,