KCNH2 Variant S182W Detail

We estimate the penetrance of LQTS for KCNH2 S182W is 9%. This variant was found in a total of 1 carriers in 0 papers or gnomAD (version 4), 0 had LQTS. S182W is present in 1 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 69% of WT with a standard error of 4%; 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. S182W has not been functionally characterized. This residue is located in a Hotspot region for LQT2. In silico predictions, functional data (if available), and location in structure are equivalent to observing 1 individuals with LQT2 and 9 unaffected individuals.These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 S182W around 9% (1/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.761 0.687 -3 0.383 43
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 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.

S182W 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
182 0 S182X,
181 4 R181fsX, R181W, R181Q,
183 4 G183fsX,
180 5
184 5 G184Del,
179 7 S179W,
185 7
178 8
186 8 G186fsX,
177 8 E177X,
187 8 G187Del, G187X, G187A, G187S,
176 9 R176X, R176W, R176Q,
188 9 A188S, A188X, A188P,
175 10 A175D, A175S, A175X,
189 10 G189Ins,
174 11
190 11 A190T, A190V,
173 11
191 11 P191fsX, P191Q,
172 12 A172V,
192 12 G192fsX,
171 13 L171Ins,
193 13 A193X, A193T, A193V, A193fsX,
170 13 L170Ins,
194 13 V194M,
169 14 A169G,
195 14
168 14
196 14
167 15
197 15 D197N, D197Y,