KCNQ1 Variant Y125S Detail

We estimate the penetrance of LQTS for KCNQ1 Y125S is 67%. We are unaware of any observations of this variant in individuals. Y125S is not present in gnomAD. Y125S 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 6 individuals with LQT1 and 4 unaffected individuals. These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 Y125S around 67% (6/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-6.92 0.974 -4 0.912 72
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 4 6 -
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.

Y125S has 45 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
125 0
126 4 H126D,
129 6 V129I,
128 6 A128del,
113 6
124 6
122 7 C122Y,
121 8
114 8
170 8
123 8
127 9 F127L, F127L, F127L,
166 9 F166V,
132 10 I132L,
117 10 P117L,
167 10
174 10 R174H, R174C, R174L,
130 11
119 11 G119R, G119V,
131 11
241 11 V241F, V241I, V241G,
110 11 V110I,
120 11 W120C, W120C,
115 11 E115A, E115G,
243 11 R243H, R243C, R243P, R243S,
173 12
169 12 T169M, T169R,
133 12 V133I,
163 12
240 12 H240R, H240P,
112 12
118 13
168 13 G168R, G168R, G168R, G168R,
111 14 Y111C,
134 14 L134P,
171 14
165 15 V165M,
202 15 D202N, D202H,
172 15 V172M, V172E,
116 15
242 15 D242N, D242Y,
177 15 S177F,
237 15
109 15 R109C, R109L,
162 15 V162M,