SCN5A Variant K1257T Detail

We estimate the penetrance of LQTS for SCN5A K1257T around 4% and the Brugada syndrome penetrance around 19%. SCN5A K1257T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. K1257T is not present in gnomAD. K1257T 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 (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 K1257T around 4% (0/10) and the Brugada syndrome penetrance around 19% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.953 19 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 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.

K1257T has 45 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
1253 6 E1253G,
1264 13 K1264R, K1264N,
1211 10
1267 10
1312 13
1270 13 A1270S,
1252 9
1262 8 G1262S,
1280 14
1271 13 W1271C,
1309 11 R1309H, R1309C,
1247 15 T1247I,
1259 8
1257 0
1268 13 T1268N, T1268S,
1256 5
1250 10
1265 12
1275 8 D1275N,
1255 8 L1255M,
1209 14 T1209R,
1251 10 V1251M,
1313 15
1279 11 V1279I,
1274 12
1258 6
1254 5
1269 11 N1269S,
1316 14 R1316Q, R1316L,
1207 9
1276 11
1215 14 I1215V,
1278 13 I1278N,
1272 7
1266 6
1260 6 A1260D,
1261 6
1249 11 V1249D,
1263 11
1208 10 E1208X, E1208K,
1277 14
1210 14 F1210S,
1214 14 M1214T,
1212 13 p.I1212del,
1273 13 W1273C, c.3816delG,