SCN5A Variant A1270S Detail

We estimate the penetrance of LQTS for SCN5A A1270S around 9% and the Brugada syndrome penetrance around 14%. SCN5A A1270S was found in a total of 1 carriers in 1 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. A1270S is not present in gnomAD. A1270S has been functionally characterized in 1 papers. This residue is located in a Mild_Hotspot region for Brugada syndrome and a Mild_Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (1 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 A1270S around 9% (0/11) and the Brugada syndrome penetrance around 14% (1/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-2.75 0.877 1.06 0.743 19 10
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
26746457 2016 1 0 0 0
LITERATURE, COHORT, AND GNOMAD: - 1 1 0 0 -
VARIANT FEATURES ALONE: - 15 14 0 1 - -
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)
26746457 2016

A1270S 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
1267 10
1328 11 V1328M,
1271 5 W1271C,
1315 12
1274 6
1258 14
1272 5
1270 0 A1270S,
1309 12 R1309H, R1309C,
1265 11
1313 14
1279 14 V1279I,
1329 14 G1329S,
1310 14
1316 14 R1316L, R1316Q,
1305 14
1273 6 W1273C, c.3816delG,
1262 13 G1262S,
1324 13
1327 14
1257 13
1268 7 T1268N, T1268S,
1275 9 D1275N,
1254 14
1263 13
1264 14 K1264R, K1264N,
1312 9
1280 14
1311 11 L1311P,
1308 11 L1308F,
1331 14 I1331V,
1269 4 N1269S,
1325 13 N1325S,
1276 10
1278 12 I1278N,
1266 9
1261 12
1277 10