SCN5A Variant I1278S Detail

We estimate the penetrance of LQTS for SCN5A I1278S around 41% and the Brugada syndrome penetrance around 15%. SCN5A I1278S was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1278S is not present in gnomAD. I1278S has been functionally characterized in 0 papers. This residue is located in a Mild_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 (1 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 I1278S around 41% (2/10) and the Brugada syndrome penetrance around 15% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.949 12 54
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 2 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.

I1278S has 60 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 13
1271 12 W1271C,
1245 15 M1245I,
1218 12 S1218I, S1218T,
1281 6 V1281F, c.3840+1G>A,
1304 9 T1304M,
1243 11 D1243N,
1274 6
1216 15 L1216V,
1285 11
1258 13
1299 15 c.3894delC,
1673 15
1272 10
1270 12 A1270S,
1252 14
1283 9 L1283M,
1309 7 R1309H, R1309C,
1242 14
1219 13 S1219N,
1251 11 V1251M,
1313 15
1279 5 V1279I,
1310 11
1306 6 R1306S, R1306H,
1286 13
1305 5
1273 9 W1273C, c.3816delG,
1246 11
1282 6 S1282A,
1302 9 p.L1302Vfs18,
1247 9 T1247I,
1257 13
1307 9
1275 5 D1275N,
1255 14 L1255M,
1222 13 L1222R, p.L1222LfsX7,
1674 14 F1674V,
1254 9
1215 11 I1215V,
1301 12
1214 14 M1214T,
1212 15 p.I1212del,
1253 10 E1253G,
1284 11
1211 13
1312 14
1280 7
1311 12 L1311P,
1308 8 L1308F,
1250 7
1670 14
1248 13
1269 14 N1269S,
1276 7
1278 0 I1278N,
1266 12
1249 11 V1249D,
1277 5
1303 10 R1303Q, R1303W,