SCN5A Variant I1299L Detail

We estimate the penetrance of LQTS for SCN5A I1299L around 8% and the Brugada syndrome penetrance around 41%. SCN5A I1299L was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1299L is not present in gnomAD. I1299L 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 (4 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 I1299L around 8% (0/10) and the Brugada syndrome penetrance around 41% (4/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.658 61 7
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 11 0 4 - -
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.

I1299L has 43 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
1297 6
1281 10 c.3840+1G>A, V1281F,
1304 12 T1304M,
1243 11 D1243N,
1285 7
1299 0 c.3894delC,
1295 11 E1295K,
1298 5 P1298L,
1283 12 L1283M,
1226 14
1288 7 A1288G,
1242 15
1239 14 L1239P,
1306 13 R1306H, R1306S,
1244 14 K1244E,
1286 11
1305 13
1282 11 S1282A,
1302 7 p.L1302Vfs18,
1247 14 T1247I,
1289 9
1678 14 N1678S,
1222 15 p.L1222LfsX7, L1222R,
1300 5
1674 15 F1674V,
1229 15
1296 11 M1296T,
1301 7
1292 10
1284 8
1734 13
1291 10
1280 14
1677 12
1240 11 E1240Q,
1225 13 G1225K, E1225K,
1287 10
1290 12
1293 12 F1293S,
1278 15 I1278N,
1236 13 K1236R, K1236N,
1294 14 A1294G,
1303 9 R1303Q, R1303W,