SCN5A Variant I1227F Detail

We estimate the penetrance of LQTS for SCN5A I1227F around 8% and the Brugada syndrome penetrance around 26%. SCN5A I1227F was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1227F is not present in gnomAD. I1227F 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 (2 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 I1227F around 8% (0/10) and the Brugada syndrome penetrance around 26% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.879 31 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 13 0 2 - -
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.

I1227F has 48 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
1233 13 K1233E,
1741 12 D1741N, D1741E, D1741Y,
1234 15
1698 11 A1698T,
1673 12
1675 12
1681 6 c.5040_5042delTTAinsC, Y1681F,
1694 10
1226 5
1695 5 Q1695X,
1688 15
1221 14 A1221V,
1676 8 M1676I, M1676T,
1692 15
1672 12 S1672Y,
1693 9
1699 11
1239 13 L1239P,
331 14
1738 15 S1738T, S1738F,
1680 7 A1680T, A1680P,
1235 11
1231 8 E1231K,
1701 15 M1701I,
1228 5 Y1228H, Y1228C, Y1228F,
1690 12 c.5068_5070delGA, D1690N,
1678 12 N1678S,
1223 11 c.3667delG,
1697 10
1222 13 p.L1222LfsX7, L1222R,
1230 9 E1230K,
1227 0
1674 15 F1674V,
1229 7
1683 14
1301 14
1696 7
1739 14 R1739W, R1739Q,
1700 12
1677 10
1682 11
1224 11
1740 12 G1740R,
1225 8 G1225K, E1225K,
1691 14
1232 14 R1232W, R1232Q,
1679 11
1236 12 K1236R, K1236N,