SCN5A Variant R277M Detail

We estimate the penetrance of LQTS for SCN5A R277M around 10% and the Brugada syndrome penetrance around 51%. SCN5A R277M was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. R277M is not present in gnomAD. R277M 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 (5 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 R277M around 10% (0/10) and the Brugada syndrome penetrance around 51% (5/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.864 78 9
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 10 0 5 - -
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.

R277M has 56 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 15
364 15
277 0
271 14 L271V,
326 13
276 6 L276P, L276Q,
348 8 P348A,
317 13 K317E, K317N, K317M,
270 14 Q270K,
360 12
279 7
385 13 A385T,
1552 14 Q1552R, Q1552L,
355 10 F355C, F355I,
1549 11
278 7 H278R, H278D,
356 7 D356N,
361 13
343 5
327 12
384 10 S384T,
354 7
349 12 D349N,
1550 7
357 11
272 11
341 11 C341Y,
274 4 G274C,
273 9
325 10 L325R,
324 13
321 12 S321Y,
269 12
345 6
275 7 N275K,
383 14
280 12 C280Y,
323 11
347 6
1548 15 G1548K, E1548K,
351 9 G351S, G351D, G351C, G351V,
320 12 T320N,
350 14 H350Q,
342 9
1551 10 D1551N, D1551Y,
346 7 E346G, E346K, E346X, E346D,
359 15 p.A359PfsX12, A359T,
344 5 A344S,
381 12 c.1140+1G>A, c.1141-3C>A,
322 12
352 12 Y352C,
380 11
268 13 G268S,
377 14
281 13 V281M,
353 9 T353I,