SCN5A Variant A124S Detail

We estimate the penetrance of LQTS for SCN5A A124S around 3% and the Brugada syndrome penetrance around 40%. SCN5A A124S was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. A124S is not present in gnomAD. A124S has been functionally characterized in 0 papers. This residue is located in a 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 (3 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 A124S around 3% (0/10) and the Brugada syndrome penetrance around 40% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.626 59 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 12 0 3 - -
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.

A124S has 38 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 6 K126E,
136 15 L136P,
175 9 K175N,
129 8
188 14
178 6 A178G,
128 6 c.381dupT,
117 14
179 9 R179X, R179Q,
119 9 P119S, P119L,
169 14
177 6 L177P,
123 4 A123G, A123V,
121 6 R121W, R121Q,
127 5
124 0 A124D,
118 11
125 4 V125L,
181 15
176 10
172 11
131 14
174 6 V174I,
133 10
115 12 S115G,
173 9
132 14 c.393-5C>A,
114 11
130 10
184 14 H184R,
116 12
180 11 G180V,
134 12 N134S,
170 10 F170I,
120 7
122 8
171 11
137 14 I137V,