SCN5A Variant I1771T Detail

We estimate the penetrance of LQTS for SCN5A I1771T around 16% and the Brugada syndrome penetrance around 11%. SCN5A I1771T was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1771T is present in 1 alleles in gnomAD. I1771T has been functionally characterized in 0 papers. This residue is located in a Non_Hotspot region for Brugada syndrome and a Mild_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 I1771T around 16% (0/11) and the Brugada syndrome penetrance around 11% (1/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-4.62 1 -3.66 0.965 6 28
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 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.

I1771T has 74 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
403 7
414 13 M414V,
939 14 L939F,
1659 13
1643 14 I1643L,
404 10 L404Q, L404V,
1778 11
1773 7
1765 11
1653 6
1472 15 N1472S, p.N1472del,
1771 0 I1771T,
401 11 S401P,
1652 9 M1652R, M1652T,
1777 11 V1777L, V1777M,
1764 11 c.5290delG, V1764F,
250 15
409 9 L409V, L409P,
928 15 L928P,
1650 7 L1650F,
1656 9
1477 12 K1477N,
1471 14
935 13 L935P,
1779 12 T1779M,
412 13 V412D,
1470 10
1466 11 c.4396_4397insG,
1776 9
369 14 M369K,
1767 6 Y1767C,
1660 11 I1660V, I1660S,
1654 10
1648 12
1769 6
402 9 F402L,
1766 10 M1766V, M1766L, M1766T,
1319 15 G1319V,
1649 8 A1649V,
1768 6 I1768V,
1774 6 N1774D, c.5321_5324dupACTT,
1473 10 F1473C, F1473S,
256 14
399 12
397 15 I397T, I397F, I397V,
405 9
1657 7
1474 13
1772 5 L1772V,
1645 13 T1645M,
1323 13 V1323G,
410 8 A410V,
1770 5 I1770V,
1651 11
413 12 A413T, A413E,
408 10
253 13
1322 14 c.3963+2T>C, c.3963+4A>G,
407 7
936 15
1763 13 V1763L, V1763M,
1467 14
1775 7 F1775V, p.F1775LfsX15,
1661 14 G1661E, G1661R,
1655 11
1469 12 I1469V,
406 6 N406S, N406K,
411 11 V411M,
932 13
398 12
1647 11
400 11 G400R, G400A, G400E,
1646 10
1658 12