KCNH2 Variant S140Y Detail

We estimate the penetrance of LQTS for KCNH2 S140Y is 7%. This variant was found in a total of 1 carriers in 0 papers or gnomAD (version 4), 0 had LQTS. S140Y is present in 1 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 138% of WT with a standard error of 15%; in our analysis we used SE < 20% as 'high quality'. Approximately below 50% of WT is considered PS3 moderate and below 30% is PS3 strong. S140Y has not been functionally characterized. This residue is located in a Non_Hotspot region for LQT2. In silico predictions, functional data (if available), and location in structure are equivalent to observing 0 individuals with LQT2 and 10 unaffected individuals.These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 S140Y around 7% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-2.069 0.578 -2 0.478 0
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 LQT2 Other Disease
LITERATURE, COHORT, AND GNOMAD: - 1 1 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.

S140Y 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 since the functional KV11.1 channel (protein product of KCNH2/hERG) 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
140 0 S140Y,
139 4 G139R, G139R, G139A,
141 4 P141L, P141fsX, P141S,
138 5
142 5 A142T,
137 7
143 7
136 8
144 8 D144V,
135 8
145 8
134 9 E134X,
146 9 N146X,
133 10 M133T,
147 10 H147X, H147R,
132 11 V132X,
148 11 R148Q, R148fsX, R148W, R148Y,
131 11 V131L, V131fsX, V131L,
149 11 G149A, G149V,
130 12 E130K,
150 12 P150L,
129 13 F129C,
151 13 P151fsX, P151X,
128 13 N128S,
152 13 T152fsX, T152X, T152I, T152S, T152S,
127 14
153 14 S153R, S153R, S153R,
126 14
154 14 W154R, W154R, W154X,
125 15
155 15