KCNQ1 Variant K285E Detail

We estimate the penetrance of LQTS for KCNQ1 K285E is 52%. We are unaware of any observations of this variant in individuals. K285E is not present in gnomAD. K285E has not been functionally characterized. This residue is located in a Hotspot region for LQT1. In silico predictions, functional data (if available), and location in structure are equivalent to observing 5 individuals with LQT1 and 5 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 K285E around 52% (5/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-3.76 0.995 -1 0.837 54
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 LQT1 Other Disease
LITERATURE, COHORT, AND GNOMAD: - 0 0 0
VARIANT FEATURES ALONE: - 10 5 5 -
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.

K285E has 47 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. This results from the fact that the functional KV7.1 channel 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
286 4
281 5 Y281C,
283 7 A283G, A283T,
297 7 G297S, G297D, G297R,
287 7 A287E, A287T, A287S,
284 7 E284K,
282 7 L282P,
296 8 F296S, F296L, F296L, F296L,
294 8 V294M,
228 9
298 9 S298I, S298N,
280 9 V280A, V280E,
144 9 T144A,
227 10
288 10
231 10 R231C, R231H, R231S,
299 10
295 10
302 11 A302V, A302E, A302T,
322 11 T322M, T322A, T322K,
278 11 Y278H,
279 12 F279I,
325 12 G325R, G325R, G325E, G325W,
277 12 S277L, S277del, S277P, S277W,
300 12 A300T, A300S,
146 12 E146K, E146G, E146Q,
324 12
145 13
224 13 T224M,
143 13 S143F, S143P, S143Y,
320 13 P320H, P320A, P320S,
223 13
229 13 G229D,
318 13
293 13 R293C, R293H,
289 13
141 13 V141M,
225 13 S225L, S225del,
226 14 A226V,
303 14 L303P,
140 14 S140G, S140R, S140R, S140R,
328 14 I328del,
276 14 S276del,
232 15
292 15 G292D,
230 15