SCN5A Variant L256F Detail

We estimate the penetrance of LQTS for SCN5A L256F around 52% and the Brugada syndrome penetrance around 9%. SCN5A L256F was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L256F is not present in gnomAD. L256F has been functionally characterized in 0 papers. This residue is located in a Non_Hotspot region for Brugada syndrome and a Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (0 diagnosed with Brugada syndrome) and 5 individuals for LQTS (2 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A L256F around 52% (2/10) and the Brugada syndrome penetrance around 9% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.893 2 71
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 2 0 - -
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.

L256F has 58 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 11
1643 7 I1643L,
404 8 L404V, L404Q,
249 14 K249X,
396 14 V396L, V396A,
1635 15
254 7
1771 14 I1771T,
401 13 S401P,
1634 9 L1634P,
250 10
1542 15
928 15 L928P,
1650 10 L1650F,
260 6
366 13
1641 14
365 14
258 7 V258A,
1639 14 G1639A,
369 11 M369K,
1648 14
1630 12 I1630V, I1630R,
1649 13 A1649V,
1644 12 R1644L, R1644C, R1644H,
1640 11
262 10 S262G,
256 0
399 13
405 12
362 14
261 9
1539 15 C1539Y, C1539F,
255 5
1645 12 T1645M,
251 9
410 14 A410V,
264 12
1651 13
259 6
1633 10
265 14 A265V,
1637 10
408 11
253 5
1636 13
407 9
263 11 V263I,
1775 14 p.F1775LfsX15, F1775V,
1642 10 G1642E,
1631 11 G1631D,
406 13 N406K, N406S,
252 8
411 13 V411M,
1647 8
257 5
400 10 G400E, G400A, G400R,
1646 8