KCNQ1 Variant R401W Detail

We estimate the penetrance of LQTS for KCNQ1 R401W is 6%. This variant was found in a total of 20 carriers in 0 papers or gnomAD, 0 had LQTS. R401W is present in 20 alleles in gnomAD. R401W 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 R401W around 6% (1/30).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-2.78 0.999 -3 0.585 9
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: - 20 20 0
VARIANT FEATURES ALONE: - 10 9 1 -
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.

R401W 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
401 0 R401W, R401Q,
400 4
402 4
399 5 A399S, A399V, A399G,
403 5 H403P,
398 7 K398R,
404 7
397 8 R397W, R397Q, R397G,
405 8
396 8
406 8
395 9 Y395C,
407 9
394 10 I394L,
408 10 P408A,
393 11 K393N,
409 11
392 11 W392R, W392R, W392ins,
410 11
391 12 T391A, T391I,
411 12
390 13
412 13 P412S,
389 13 S389P,
413 13 K413R,
388 14 D388H, D388N,
414 14
387 14 P387T,
415 14
386 15 N386K, N386K,
416 15 V416M,