SCN5A Variant T1606I Detail

We estimate the penetrance of LQTS for SCN5A T1606I around 5% and the Brugada syndrome penetrance around 16%. SCN5A T1606I was found in a total of 3 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T1606I is present in 3 alleles in gnomAD. T1606I 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 (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 T1606I around 5% (0/13) and the Brugada syndrome penetrance around 16% (2/13).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
0.35 0.005 5.8 0.492 29 4
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: - 3 3 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.

T1606I has 39 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 13 F1567L,
1566 12
1568 8
1602 5
1558 14
1601 9 L1601H,
1609 7 S1609W, S1609L,
1557 15 I1557V,
1562 12
1608 6
1613 13 Q1613H, Q1613L,
1600 10
1571 13 F1571C,
1572 11
1564 9
1570 14 p.1570_F1571insI, I1570V, p.I1570dup,
1599 10
1626 12 R1626L, R1626P, R1626H, R1626C,
1603 6 I1603F,
1625 15
1606 0 T1606I,
1560 14 L1560F,
1610 10 D1610G,
1597 14 V1597M,
1565 7 L1565M,
1619 12 c.4856delC, P1619L, P1619Q,
1605 4 G1605C, G1605D, c.4813+3_4813+6dupGGGT, c.4813+5insTGGG, c.4813+2_4813+5dupTGGG,
1611 13 I1611V,
1563 13
1616 12
1607 4
1617 10 p.F1617del,
1604 7 V1604M, c.4810+3_4810+6dupGGGT,
1622 10
1618 13
1598 12 V1598A,
1561 10
1623 14 R1623X, R1623Q, R1623L, c.4867delC,