SCN5A Variant A251G Detail

We estimate the penetrance of LQTS for SCN5A A251G around 29% and the Brugada syndrome penetrance around 9%. SCN5A A251G was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. A251G is not present in gnomAD. A251G 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 (0 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 A251G around 29% (1/10) 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 0.765 3 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 14 1 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.

A251G has 44 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
414 14 M414V,
1643 9 I1643L,
404 13 L404Q, L404V,
249 8 K249X,
247 7 V247L,
254 5
250 5
928 13 L928P,
925 14 I925F,
260 14
1641 14
258 11 V258A,
1639 14 G1639A,
246 10
412 13 V412D,
924 12 V924I,
245 11 Q245K,
244 12
415 14 A415T,
1640 11
256 9
921 15
405 15
248 8
261 15
255 6
1645 14 T1645M,
251 0
410 13 A410V,
242 15 A242D,
929 13
259 14
1637 14
408 11
253 5
407 11
1775 15 F1775V, p.F1775LfsX15,
1642 9 G1642E,
252 4
411 10 V411M,
243 14
1647 14
257 9
1646 12