KCNQ1 Variant P408A Detail

We estimate the penetrance of LQTS for KCNQ1 P408A is 0%. This variant was found in a total of 460 carriers in 3 papers or gnomAD, 0 had LQTS. P408A is present in 451 alleles in gnomAD. P408A 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 0 individuals with LQT1 and 10 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 P408A around 0% (0/470).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
24
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
29197658 2018 4 None 4 None
22949429 2012 9 9 None None
19841300 2009 9 9 None None
LITERATURE, COHORT, AND GNOMAD: - 460 460 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.

P408A 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
408 0 P408A,
407 4
409 4
406 5
410 5
405 7
411 7
404 8
412 8 P412S,
403 8 H403P,
413 8 K413R,
402 9
414 9
401 10 R401W, R401Q,
415 10
400 11
416 11 V416M,
399 11 A399S, A399V, A399G,
417 11 V417M,
398 12 K398R,
418 12 V418I,
397 13 R397W, R397Q, R397G,
419 13
396 13
420 13 K420E, K420N, K420N,
395 14 Y395C,
421 14 K421N, K421N,
394 14 I394L,
422 14 K422T, K422R,
393 15 K393N,
423 15