SCN5A Variant M1546T Detail

We estimate the penetrance of LQTS for SCN5A M1546T around 8% and the Brugada syndrome penetrance around 13%. SCN5A M1546T was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. M1546T is present in 1 alleles in gnomAD. M1546T has been functionally characterized in 0 papers. This residue is located in a Mild_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 M1546T around 8% (0/11) and the Brugada syndrome penetrance around 13% (1/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-5.53 0.973 -0.87 0.872 12 7
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: - 1 1 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.

M1546T 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
364 15
271 13 L271V,
266 5 L266H,
363 15
1544 7 T1544P,
270 9 Q270K,
360 13
1627 10
1567 14 F1567L,
1624 14 V1624I,
1536 14
1552 14 Q1552R, Q1552L,
355 12 F355I, F355C,
1549 10
1538 12
1556 13
356 12 D356N,
1543 5 V1543A, V1543L,
1542 6
361 10
260 13
365 13
1564 13
258 12 V258A,
354 15
1546 0 M1546T,
1545 6
1630 12 I1630V, I1630R,
1626 12 R1626C, R1626L, R1626P, R1626H,
267 10
1550 14
1560 11 L1560F,
262 7 S262G,
357 9
272 15
362 10
261 12
273 12
1559 15 I1559V,
1628 14
1539 10 C1539Y, C1539F,
269 8
1537 14
264 12
259 12
1548 7 E1548K, G1548K,
265 8 A265V,
358 5
263 9 V263I,
359 10 A359T, p.A359PfsX12,
1547 6 V1547L,
1563 13
1541 9
1540 10
268 10 G268S,
1623 12 R1623Q, c.4867delC, R1623L, R1623X,