SCN5A Variant L324I Detail

We estimate the penetrance of LQTS for SCN5A L324I around 4% and the Brugada syndrome penetrance around 45%. SCN5A L324I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L324I is not present in gnomAD. L324I 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 (4 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 L324I around 4% (0/10) and the Brugada syndrome penetrance around 45% (4/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.624 68 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 11 0 4 - -
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.

L324I has 55 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
328 14
333 10 c.998+1G>A, c.998+5G>A,
277 13
326 7
276 11 L276Q, L276P,
348 9 P348A,
279 8
385 13 A385T,
1687 12
278 11 H278D, H278R,
334 10 c.999-424_1338+81del,
332 12 A332T,
327 10
339 11
376 10 R376H, R376C,
384 10 S384T,
1688 14
1684 13 W1684R,
282 14 R282C, R282H,
1692 12
386 14 G386E, G386R,
378 14
349 10 D349N,
379 10
341 12 C341Y,
274 15 G274C,
335 11 C335R, C335S,
325 5 L325R,
1690 12 c.5068_5070delGA, D1690N,
324 0
321 10 S321Y,
345 13
275 14 N275K,
383 6
280 7 C280Y,
323 4
347 12
382 12
351 14 G351D, G351V, G351S, G351C,
320 13 T320N,
1689 9 D1689N,
350 15 H350Q,
342 13
346 14 E346K, E346X, E346G, E346D,
336 11 P336L,
344 13 A344S,
381 12 c.1140+1G>A, c.1141-3C>A,
1686 13
322 8
375 14
1691 12
380 8
377 13
281 11 V281M,
353 13 T353I,