KCNH2 Variant F163S Detail

We estimate the penetrance of LQTS for KCNH2 F163S is 9%. We are unaware of any observations of this variant in individuals. F163S is not present in gnomAD. We have tested the trafficking efficiency of this variant, 126% of WT with a standard error of 17%; 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. F163S has not been functionally characterized. This residue is located in a Mild_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 F163S around 9% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-3.071 0.885 -4 0.719 29
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: - 0 0 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.

F163S 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
163 0
162 4 T162X,
164 4 R164H, R164C,
161 5
165 5
160 7
166 7
159 8
167 8
158 8
168 8
157 9 P157X,
169 9 A169G,
156 10
170 10 L170Ins,
155 11
171 11 L171Ins,
154 11 W154R, W154R, W154X,
172 11 A172V,
153 12 S153R, S153R, S153R,
173 12
152 13 T152X, T152S, T152I, T152fsX, T152S,
174 13
151 13 P151X, P151fsX,
175 13 A175S, A175X, A175D,
150 14 P150L,
176 14 R176W, R176Q, R176X,
149 14 G149V, G149A,
177 14 E177X,
148 15 R148W, R148Q, R148fsX, R148Y,
178 15