SCN5A Variant S115G Detail

We estimate the penetrance of LQTS for SCN5A S115G around 62% and the Brugada syndrome penetrance around 7%. SCN5A S115G was found in a total of 1 carriers in 1 papers and/or in gnomAD: 0 had Brugada syndrome, 1 had LQTS. S115G is not present in gnomAD. S115G has been functionally characterized in 1 papers. This residue is located in a Non_Hotspot region for Brugada syndrome and a Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (0 diagnosed with Brugada syndrome) and 5 individuals for LQTS (2 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A S115G around 62% (3/11) and the Brugada syndrome penetrance around 7% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-3.53 0.688 0.99 0.833 4 73
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
19716085 2009 1 1 0 0
LITERATURE, COHORT, AND GNOMAD: - 1 0 1 0 -
VARIANT FEATURES ALONE: - 15 13 2 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.

Functional Data

Peak and late/persistent current are relative to wildtype (100% being no different from wildtype). V0.5 act/inact are the voltages at which half of the maximal current is reached during an activation and inactivation protocol, each is in units of mV and relative to wildtype.
PubMed ID Year Cell Type Peak Current (%WT) V1/2 Act. (mV) V1/2 Inact. (mV) Late/Persistent Current (%WT)
19716085 2009

S115G has 25 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 14 K126E,
113 7 V113I, V113A,
178 10 A178G,
117 5
119 9 P119L, P119S,
179 11 R179X, R179Q,
177 10 L177P,
123 13 A123G, A123V,
121 6 R121Q, R121W,
124 12 A124D,
118 5
125 12 V125L,
181 10
176 13
174 15 V174I,
115 0 S115G,
182 13 C182R, C182Y,
112 7 Y112C,
114 5
184 11 H184R,
116 4
180 9 G180V,
120 10
183 12
122 8