SCN5A Variant V255G Detail

We estimate the penetrance of LQTS for SCN5A V255G around 48% and the Brugada syndrome penetrance around 10%. SCN5A V255G was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. V255G is not present in gnomAD. V255G 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 V255G around 48% (2/10) and the Brugada syndrome penetrance around 10% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.934 2 64
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.

V255G 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
1643 8 I1643L,
404 11 L404Q, L404V,
249 13 K249X,
247 13 V247L,
254 6
1634 12 L1634P,
250 9
1650 15 L1650F,
260 9
366 14
1641 14
258 6 V258A,
1639 13 G1639A,
924 15 V924I,
369 14 M369K,
1630 14 I1630R, I1630V,
1640 10
1644 13 R1644L, R1644H, R1644C,
262 11 S262G,
256 5
362 13
248 14
261 10
1539 14 C1539F, C1539Y,
255 0
1645 14 T1645M,
251 6
259 8
1633 11
1637 11
408 13
253 6
1636 13
407 12
263 13 V263I,
1642 11 G1642E,
1631 14 G1631D,
252 6
411 14 V411M,
1647 11
257 6
400 15 G400R, G400A, G400E,
1646 11