KCNH2 Variant P297S Detail

We estimate the penetrance of LQTS for KCNH2 P297S is 2%. This variant was found in a total of 35 carriers in 2 papers or gnomAD (version 4), 0 had LQTS. P297S is present in 33 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 83% of WT with a standard error of 19%; 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. P297S 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 P297S around 2% (0/45).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.238 0.149 0 0.592 1
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
France Cohort 2020 1 1 0
22882672 2012 1 1
LITERATURE, COHORT, AND GNOMAD: - 35 6 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.

P297S 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
297 0 P297S,
296 4 L296fsX,
298 4 P298X,
295 5 V295fsX,
299 5
294 7
300 7
293 8
301 8
292 8
302 8 H302fsX, H302X, H302H,
291 9
303 9
290 10
304 10 S304R, S304R, S304R,
289 11 E289K,
305 11
288 11
306 11 G306W,
287 12 D287fsX,
307 12 A307P,
286 13 D286X,
308 13 M308I, M308I, M308V, M308T, M308R, M308I,
285 13 A285V, A285fsX,
309 13 H309Y, H309Q, H309Q,
284 14 S284X,
310 14 P310X, P310L,
283 14
311 14 L311R,
282 15 A282X,
312 15 R312H, R312Del, R312C,