SCN5A Variant V323G Detail

We estimate the penetrance of LQTS for SCN5A V323G around 4% and the Brugada syndrome penetrance around 39%. SCN5A V323G was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. V323G is not present in gnomAD. V323G has been functionally characterized in 0 papers. This residue is located in a 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 (3 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 V323G around 4% (0/10) and the Brugada syndrome penetrance around 39% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.663 57 2
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 0 3 - -
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.

V323G has 49 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
333 13 c.998+1G>A, c.998+5G>A,
277 11
326 8
276 11 L276Q, L276P,
348 8 P348A,
317 14 K317M, K317E, K317N,
279 5
338 14
278 10 H278R, H278D,
334 13 c.999-424_1338+81del,
332 15 A332T,
343 13
327 11
339 11
376 13 R376H, R376C,
384 12 S384T,
354 14
282 11 R282H, R282C,
340 14 R340W, R340Q,
349 10 D349N,
283 15
379 14
341 11 C341Y,
274 14 G274C,
335 12 C335R, C335S,
319 11 G319C, G319S, G319R,
325 6 L325R,
324 4
321 6 S321Y,
872 14 D872N,
345 10
275 14 N275K,
383 10
280 6 C280Y,
323 0
347 10
351 13 G351S, G351V, G351D, G351C,
320 9 T320N,
1689 13 D1689N,
350 13 H350Q,
342 11
346 10 E346D, E346K, E346X, E346G,
336 12 P336L,
344 10 A344S,
381 14 c.1140+1G>A, c.1141-3C>A,
322 5
380 10
281 9 V281M,
353 13 T353I,