SCN5A Variant T257A Detail

We estimate the penetrance of LQTS for SCN5A T257A around 58% and the Brugada syndrome penetrance around 9%. SCN5A T257A was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T257A is not present in gnomAD. T257A has been functionally characterized in 0 papers. This residue is located in a Non_Hotspot region for Brugada syndrome and a Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (0 diagnosed with Brugada syndrome) and 5 individuals for LQTS (2 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A T257A around 58% (2/10) and the Brugada syndrome penetrance around 9% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.961 1 79
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 13 2 0 - -
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.

T257A has 62 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
403 11
364 14
266 15 L266H,
363 14
1643 10 I1643L,
404 6 L404Q, L404V,
249 15 K249X,
396 12 V396L, V396A,
247 14 V247L,
254 5
401 10 S401P,
1634 13 L1634P,
371 15 Q371E,
250 9
409 14 L409V, L409P,
928 12 L928P,
1650 13 L1650F,
361 14
260 5
366 9
365 11
258 4 V258A,
924 12 V924I,
369 8 M369K,
402 14 F402L,
1630 14 I1630R, I1630V,
1640 15
262 9 S262G,
256 5
399 13
397 14 I397V, I397F, I397T,
405 10
362 10
261 6
920 13
255 6
395 15
251 9
410 14 A410V,
264 11
929 15
259 7
1633 13
265 12 A265V,
1637 14
408 9
253 6
407 9
358 14
263 10 V263I,
370 12 T370M,
1642 14 G1642E,
923 14
1631 14 G1631D,
406 12 N406S, N406K,
368 13
252 10
411 13 V411M,
1647 12
257 0
400 9 G400A, G400E, G400R,
1646 12