SCN5A Variant L1621H Detail

We estimate the penetrance of LQTS for SCN5A L1621H around 30% and the Brugada syndrome penetrance around 24%. SCN5A L1621H was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L1621H is not present in gnomAD. L1621H has been functionally characterized in 0 papers. This residue is located in a Mild_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 (2 diagnosed with Brugada syndrome) and 5 individuals for LQTS (1 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A L1621H around 30% (1/10) and the Brugada syndrome penetrance around 24% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.971 27 38
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 12 1 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.

L1621H has 43 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
271 10 L271V,
266 14 L266H,
270 11 Q270K,
1627 10
385 15 A385T,
1624 5 V1624I,
391 12
388 12 I388S,
1602 12
1601 9 L1601H,
1613 13 Q1613H, Q1613L,
1600 13
1615 14 Y1615X,
1599 14
1545 14
1626 10 R1626P, R1626C, R1626L, R1626H,
267 11
1603 15 I1603F,
1625 6
272 14
1596 15 F1596I, F1596C,
1628 11
1597 10 V1597M,
392 13
389 11 Y389H, Y389X,
1620 4 T1620M, T1620K,
395 14
1594 12 F1594S,
264 15
1614 12
1595 15
1619 7 P1619L, P1619Q, c.4856delC,
1629 14 R1629X, R1629G, R1629Q,
1605 13 c.4813+3_4813+6dupGGGT, G1605C, c.4813+5insTGGG, c.4813+2_4813+5dupTGGG, G1605D,
1616 12
1617 7 p.F1617del,
268 13 G268S,
1604 12 c.4810+3_4810+6dupGGGT, V1604M,
1622 7
1618 5
1621 0
1598 10 V1598A,
1623 7 c.4867delC, R1623X, R1623L, R1623Q,