SCN5A Variant L269M Detail

We estimate the penetrance of LQTS for SCN5A L269M around 15% and the Brugada syndrome penetrance around 18%. SCN5A L269M was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L269M is not present in gnomAD. L269M has been functionally characterized in 0 papers. This residue is located in a Mild_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 (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 L269M around 15% (0/10) and the Brugada syndrome penetrance around 18% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.775 20 18
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 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.

L269M has 63 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
364 11
277 12
271 7 L271V,
266 5 L266H,
276 11 L276P, L276Q,
363 13
1544 11 T1544P,
270 4 Q270K,
360 11
1627 11
396 14 V396L, V396A,
385 15 A385T,
1624 12 V1624I,
1552 13 Q1552R, Q1552L,
355 6 F355I, F355C,
1549 8
278 15 H278D, H278R,
1556 15
356 7 D356N,
1543 12 V1543A, V1543L,
1542 11
1557 15 I1557V,
361 7
343 14
365 11
354 9
1546 8 M1546T,
1545 8
1626 13 R1626H, R1626L, R1626P, R1626C,
267 7
1550 9
1560 14 L1560F,
262 10 S262G,
357 7
272 7
274 9 G274C,
362 11
261 13
273 5
392 11
389 13 Y389X, Y389H,
269 0
1620 12 T1620K, T1620M,
393 14
275 10 N275K,
264 11
347 14
1548 7 G1548K, E1548K,
265 6 A265V,
1619 13 P1619Q, c.4856delC, P1619L,
358 6
1551 12 D1551N, D1551Y,
263 11 V263I,
359 9 A359T, p.A359PfsX12,
1547 9 V1547L,
1541 13
381 14 c.1141-3C>A, c.1140+1G>A,
368 14
268 4 G268S,
377 14
1622 15
353 13 T353I,
1623 9 R1623L, R1623X, R1623Q, c.4867delC,