KCNH2 Variant P241S Detail

We estimate the penetrance of LQTS for KCNH2 P241S is 4%. This variant was found in a total of 15 carriers in 0 papers or gnomAD (version 4), 0 had LQTS. P241S is present in 15 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 98% of WT with a standard error of 27%; 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. P241S 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 P241S around 4% (0/25).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-0.564 0.138 -1 0.337 38
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: - 15 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.

P241S 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
241 0 P241fsX, P241L, P241S,
240 4 P240L,
242 4 R242X, R242C,
239 5 S239X, S239P,
243 5 S243R, S243X, S243R, S243R,
238 7 G238R, G238D, G238S,
244 7 A244G, A244E,
237 8
245 8 P245R,
236 8 G236V,
246 8
235 9
247 9 Q247X, Q247R,
234 10 L234Del,
248 10
233 11 A233S,
249 11
232 11 R232P, R232C,
250 11
231 12
251 12 P251A,
230 13 E230D, E230D,
252 13 R252Q, R252fsX,
229 13 E229X,
253 13
228 14 A228X, A228V, A228T, A228P,
254 14 H254Q, H254X, H254Q,
227 14
255 14
226 15
256 15