KCNQ1 Variant V599L Detail

We estimate the penetrance of LQTS for KCNQ1 V599L is 52%. We are unaware of any observations of this variant in individuals. V599L is not present in gnomAD. V599L 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 V599L around 52% (5/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-0.34 0.002 1 0.616 59
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.

V599L 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
599 0
598 4 K598R,
600 4 T600M,
597 5
601 5
596 7 E596del, E596K,
602 7
595 8 V595L, V595L,
603 8
594 8 R594Q, R594P,
604 8
593 9 N593S,
605 9
592 10
606 10
591 11 R591H, R591C, R591L,
607 11 A607T,
590 11 A590T,
608 11
589 12 G589D, G589S,
609 12
588 13 I588F,
610 13
587 13 T587M, T587R,
611 13 D611N, D611Y,
586 14 N586D,
612 14
585 14 S585N,
613 14
584 15 G584S,
614 15 H614del,