KCNH2 Variant A285V Detail

We estimate the penetrance of LQTS for KCNH2 A285V is 4%. This variant was found in a total of 1 carriers in 0 papers or gnomAD, 0 had LQTS. A285V is present in 1 alleles in gnomAD. A285V 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 A285V around 4% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
0.643 0.014 5 0.485 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.

A285V 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
285 0 A285V, A285fsX,
284 4 S284X,
286 4 D286X,
283 5
287 5 D287fsX,
282 7 A282X,
288 7
281 8 R281fsX, R281X,
289 8 E289K,
280 8
290 8
279 9
291 9
278 10
292 10
277 11
293 11
276 11 C276X,
294 11
275 12 S275R, S275R, S275R,
295 12 V295fsX,
274 13 E274X,
296 13 L296fsX,
273 13 R273X, R273Q,
297 13 P297S,
272 14
298 14 P298X,
271 14 R271L,
299 14
270 15
300 15