SCN5A Variant M1320T Detail

We estimate the penetrance of LQTS for SCN5A M1320T around 8% and the Brugada syndrome penetrance around 19%. SCN5A M1320T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. M1320T is not present in gnomAD. M1320T 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 M1320T around 8% (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 0.979 19 6
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.

M1320T has 52 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
1328 11 V1328M,
1659 5
1271 13 W1271C,
1480 13 c.4438-1C>T, c.4437+5G>A,
1653 13
1315 5
1314 5 c.3940_3941delCT,
1320 0 M1320I,
1764 15 V1764F, c.5290delG,
1666 11
1656 8
1477 13 K1477N,
1762 14 p.I1762del, I1762M,
1767 12 Y1767C,
1313 9
1660 7 I1660V, I1660S,
1654 14
1329 14 G1329S,
1310 12
1769 14
1316 10 R1316L, R1316Q,
1766 10 M1766V, M1766L, M1766T,
1319 4 G1319V,
1665 13
1479 15
1473 12 F1473C, F1473S,
1663 7
1657 10
1662 7
1324 6
1317 6 F1317C,
1327 10
1758 15 p.I1758del, I1758V,
1318 8
1330 15 A1330T, A1330D, A1330P,
1321 7 R1321K,
1323 4 V1323G,
1770 12 I1770V,
1212 15 p.I1212del,
1322 6 c.3963+4A>G, c.3963+2T>C,
1312 10
1326 10 A1326S,
1763 11 V1763M, V1763L,
1311 10 L1311P,
1476 12 Q1476X, Q1476R,
1661 9 G1661R, G1661E,
1655 10
1469 15 I1469V,
1325 9 N1325S,
1667 13 V1667I,
1664 11
1658 10