KCNH2 Variant E230D Detail

We estimate the penetrance of LQTS for KCNH2 E230D is 7%. This variant was found in a total of 3 carriers in 0 papers or gnomAD (version 4), 0 had LQTS. E230D is present in 3 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 70% of WT with a standard error of 10%; 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. E230D 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 E230D around 7% (0/13).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-0.062 0.001 5 0.398 7
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: - 3 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.

E230D 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
230 0 E230D, E230D,
229 4 E229X,
231 4
228 5 A228T, A228V, A228X, A228P,
232 5 R232C, R232P,
227 7
233 7 A233S,
226 8
234 8 L234Del,
225 8
235 8
224 9
236 9 G236V,
223 10
237 10
222 11 V222L, V222L,
238 11 G238R, G238D, G238S,
221 11
239 11 S239X, S239P,
220 12
240 12 P240L,
219 13 D219V,
241 13 P241fsX, P241L, P241S,
218 13
242 13 R242C, R242X,
217 14
243 14 S243X, S243R, S243R, S243R,
216 14 T216A,
244 14 A244G, A244E,
215 15 V215X, V215G,
245 15 P245R,