SCN5A Variant V125G Detail

We estimate the penetrance of LQTS for SCN5A V125G around 5% and the Brugada syndrome penetrance around 27%. SCN5A V125G was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. V125G is not present in gnomAD. V125G has been functionally characterized in 0 papers. This residue is located in a Mild_Hotspot region for Brugada syndrome and a Non_Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (2 diagnosed with Brugada syndrome) and 5 individuals for LQTS (0 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A V125G around 5% (0/10) and the Brugada syndrome penetrance around 27% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.941 34 1
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 BrS/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 LQT3 BrS1 Other Other Disease
LITERATURE, COHORT, AND GNOMAD: - 0 0 0 0 -
VARIANT FEATURES ALONE: - 15 13 0 2 - -
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.

V125G has 36 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. 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
126 5 K126E,
175 9 K175N,
113 14 V113A, V113I,
129 6
188 13
178 5 A178G,
128 6 c.381dupT,
117 13
179 7 R179X, R179Q,
119 10 P119S, P119L,
177 8 L177P,
123 5 A123G, A123V,
121 6 R121W, R121Q,
127 6
124 4 A124D,
118 11
125 0 V125L,
176 11
172 13
131 13
174 8 V174I,
133 10
115 12 S115G,
173 11
132 14 c.393-5C>A,
112 13 Y112C,
114 11
130 10
184 13 H184R,
116 10
180 11 G180V,
134 12 N134S,
170 13 F170I,
120 9
122 7
171 13