SCN5A Variant N1678S Detail

We estimate the penetrance of LQTS for SCN5A N1678S around 2% and the Brugada syndrome penetrance around 6%. SCN5A N1678S was found in a total of 7 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. N1678S is present in 7 alleles in gnomAD. N1678S has been functionally characterized in 0 papers. This residue is located in a Non_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 (0 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 N1678S around 2% (0/17) and the Brugada syndrome penetrance around 6% (0/17).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-3.59 0.886 -1.89 0.614 7 0
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: - 7 7 0 0 -
VARIANT FEATURES ALONE: - 15 15 0 0 - -
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.

N1678S 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
1746 10 A1746V, A1746T,
1741 13 D1741N, D1741E, D1741Y,
1304 10 T1304M,
1745 10
1299 14 c.3894delC,
1673 9
1675 5
1743 9 G1743E, G1743R,
1754 13
1681 12 Y1681F, c.5040_5042delTTAinsC,
1694 9
1704 14 L1704H,
1298 14 P1298L,
1226 10
1747 6 V1747M,
1695 12 Q1695X,
1716 14 p.L1716SfsX71,
1669 15
1671 10
1676 7 M1676I, M1676T,
1744 8 S1744I,
1721 12
1753 14 T1753A,
1672 10 S1672Y,
1742 11
1693 13
1305 13
1680 7 A1680T, A1680P,
1703 14
1302 12 p.L1302Vfs18,
1719 14
1307 15
1678 0 N1678S,
1223 15 c.3667delG,
1755 14
1222 14 L1222R, p.L1222LfsX7,
1227 12
1300 9
1674 6 F1674V,
1748 9 p.G1748del, G1748D,
1683 14
1301 8
1696 14
1700 12
1717 14 L1717P,
1734 15
1751 8
1677 4
1682 10
1750 11 L1750F,
1752 12
1722 14 N1722D,
1670 13
1749 12 I1749N,
1740 11 G1740R,
1225 13 G1225K, E1225K,
1720 10 c.5157delC,
1732 13
1679 5
1303 14 R1303W, R1303Q,