SCN5A Variant G298S Detail

We estimate the penetrance of LQTS for SCN5A G298S around 1% and the Brugada syndrome penetrance around 7%. SCN5A G298S was found in a total of 7 carriers in 1 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. G298S is present in 7 alleles in gnomAD. G298S has been functionally characterized in 2 papers. This residue is located in a Non_Hotspot region for Brugada syndrome and a Non_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 G298S around 1% (0/17) and the Brugada syndrome penetrance around 7% (1/17).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-0.47 0.824 -0.21 0.551 3 1
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
11804990 2002 1 0 0 1 AV block
LITERATURE, COHORT, AND GNOMAD: - 7 7 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.

Functional Data

Peak and late/persistent current are relative to wildtype (100% being no different from wildtype). V0.5 act/inact are the voltages at which half of the maximal current is reached during an activation and inactivation protocol, each is in units of mV and relative to wildtype.
PubMed ID Year Cell Type Peak Current (%WT) V1/2 Act. (mV) V1/2 Inact. (mV) Late/Persistent Current (%WT)
19056759 2009 HEK 50
11804990 2002 HEK-tSA204 85 3.6 7.4

G298S has 31 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
283 15
284 14
285 14 T285K,
286 13 A286V, A286S,
287 13
288 12 N288S,
289 11 G289S,
290 11 p.T290_G292del,
291 10 p.N291TfsX52, N291H, N291S, p.N291_S293dup, N291K,
292 9 G292S,
293 8
294 8 V294M,
295 7 E295K,
296 5
297 4
298 0 G298S, G298D,
299 4 L299M, L299F,
300 5 V300I,
301 7
302 8
303 8
304 9
305 10 D305N,
306 11 L306V, L306F,
307 11
308 12
309 13 S309C, S309N,
310 13 D310N,
311 14
312 14 E312K, c.934+4C>T, c.934+1G>A,
313 15