KCNQ1 Variant G186D Detail

We estimate the penetrance of LQTS for KCNQ1 G186D is 36%. This variant was found in a total of 2 carriers in 2 papers or gnomAD, 0 had LQTS. G186D is not present in gnomAD. G186D has been functionally characterized in 1 papers. 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 4 individuals with LQT1 and 6 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 G186D around 36% (4/12).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-6.19 1.0 -1 0.951 42
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
30758498 2019 2 2 None None
27041150 2016 3 2 None None
LITERATURE, COHORT, AND GNOMAD: - 2 2 0
VARIANT FEATURES ALONE: - 10 6 4 -
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.

Functional Data Homozygously Collected

Peak current is relative to wildtype (100% being no different from wildtype). V0.5 activation is the voltages at which half of the maximal current is reached during an activation in units of mV and relative to wildtype. Recovery from inactivation (Rec. inact.) and deactivation time (Deactivation) are the ratio of characteristic time constants with wildtype (unitless).

PubMed ID Cell Type Peak Current IKs (%WT) V1/2 Act. Activation time (%WT) Deactivation time (%WT)
34930020 HEK 6 None 0.78 None

Functional Data Heterozygously Collected

Functional parameters are the same as defined above.

PubMed ID Cell Type Peak Current IKs (%WT) V1/2 Act. Activation time (%WT) Deactivation time (%WT)
34930020 HEK 32 0.71 1.2 0.92

G186D has 26 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
186 0 G186R, G186D,
185 4 V185L, V185L, V185M, V185del,
190 5 R190W, R190Q, R190L,
187 5 L187P, L187F,
189 5 G189R, G189R, G189E,
188 5 W188C, W188C, W188G, W188S,
179 7 G179S,
191 8
184 8 Y184S, Y184C, Y184D, Y184H,
178 8 A178T, A178del,
192 9 R192C, R192H,
182 10
175 10 L175I,
193 10 F193L, F193L, F193L,
183 10 K183R,
177 11 S177F,
180 11
181 11 R181C,
176 11
194 12 A194P, A194T,
195 13 R195Q, R195W,
107 13 Q107H, Q107H,
172 14 V172M, V172E,
111 14 Y111C,
173 15
171 15