KCNQ1 Variant I574F Detail

We estimate the penetrance of LQTS for KCNQ1 I574F is 16%. We are unaware of any observations of this variant in individuals. I574F is not present in gnomAD. I574F 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 1 individuals with LQT1 and 9 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 I574F around 16% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.15 0.475 -1 0.727 19
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 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.

I574F 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
574 0 I574V,
573 4 F573L, F573L, F573L,
575 4
572 5
576 5 V576I,
571 7 S571L, S571P,
577 7
570 8 P570L,
578 8 E578K, E578V,
569 8 K569E,
579 8
568 9 G568R, G568R, G568E,
580 9 S580G, S580N,
567 10 I567T, I567S,
581 10
566 11 S566F, S566Y, S566P,
582 11
565 11
583 11 R583H, R583C, R583G,
564 12 D564H, D564N,
584 12 G584S,
563 13
585 13 S585N,
562 13 R562M, R562S, R562S,
586 13 N586D,
561 14
587 14 T587M, T587R,
560 14
588 14 I588F,
559 15 L559P,
589 15 G589D, G589S,