SCN5A Variant I1603F Detail

We estimate the penetrance of LQTS for SCN5A I1603F around 2% and the Brugada syndrome penetrance around 19%. SCN5A I1603F was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1603F is present in 1 alleles in gnomAD. I1603F 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 I1603F around 2% (0/11) and the Brugada syndrome penetrance around 19% (2/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-3.03 0.891 0.51 0.962 26 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: - 1 1 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.

I1603F has 40 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
1569 10 A1569P,
1567 14 F1567L,
1566 14
1568 8
1602 4
1601 6 L1601H,
1609 10 S1609W, S1609L,
1575 12 C1575S,
1608 7
1613 15 Q1613H, Q1613L,
1600 5
1571 12 F1571C,
1572 9
1564 13
1570 14 p.1570_F1571insI, I1570V, p.I1570dup,
1599 6
1626 13 R1626L, R1626P, R1626H, R1626C,
1603 0 I1603F,
1625 13
1606 6 T1606I,
1610 12 D1610G,
1576 13
1596 10 F1596C, F1596I,
1597 10 V1597M,
1573 13
1565 11 L1565M,
1595 13
1619 14 c.4856delC, P1619L, P1619Q,
1605 6 G1605C, G1605D, c.4813+3_4813+6dupGGGT, c.4813+5insTGGG, c.4813+2_4813+5dupTGGG,
1611 14 I1611V,
1574 14 c.4719C>T, E1574K,
1616 11
1607 5
1617 10 p.F1617del,
1604 5 V1604M, c.4810+3_4810+6dupGGGT,
1622 10
1618 13
1621 15
1598 9 V1598A,
1561 15