KCNQ1 Variant Q359P Detail

We estimate the penetrance of LQTS for KCNQ1 Q359P is 59%. We are unaware of any observations of this variant in individuals. Q359P is not present in gnomAD. Q359P has not been functionally characterized. 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 5 individuals with LQT1 and 5 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 Q359P around 59% (5/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-5.48 0.812 1 0.919 64
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 5 5 -
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.

Q359P has 17 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
354 11
535 11
358 12 K358T,
259 12 R259C, R259H, R259L, R259G,
361 13
534 13
363 13 H363N,
254 14 V254M, V254L, V254L,
353 14 L353P,
257 14 I257V,
360 14 R360ins, R360G, R360M,
351 14 F351L, F351L, F351L, F351S,
258 14 H258P, H258N, H258R, H258Y,
362 15 K362R, K362del,
539 15 R539W, R539L, R539Q,
357 15 Q357H, Q357H,
261 15 E261K, E261D, E261D, E261G, E261Q,