SCN5A Variant L261I Detail

We estimate the penetrance of LQTS for SCN5A L261I around 18% and the Brugada syndrome penetrance around 8%. SCN5A L261I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L261I is not present in gnomAD. L261I has been functionally characterized in 0 papers. This residue is located in a Non_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 (0 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 L261I around 18% (0/10) and the Brugada syndrome penetrance around 8% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.757 2 21
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 15 0 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.

L261I has 66 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 13
364 9
266 10 L266H,
363 10
404 9 L404V, L404Q,
270 15 Q270K,
360 14
1627 13
396 9 V396L, V396A,
355 12 F355I, F355C,
254 10
372 15
401 10 S401P,
1543 15 V1543L, V1543A,
371 14 Q371E,
250 15
1542 12
928 15 L928P,
361 9
260 5
366 7
365 6
258 5 V258A,
924 14 V924I,
1546 12 M1546T,
369 7 M369K,
402 14 F402L,
1630 13 I1630R, I1630V,
267 10
262 5 S262G,
357 14
256 9
399 12
397 12 I397T, I397V, I397F,
405 13
261 0
362 6
920 13
1628 15
392 12
255 10
269 13
395 12
393 14
251 15
916 15
264 7
259 7
1633 14
265 7 A265V,
408 14
253 12
407 14
358 9
367 12 R367L, R367C, R367H,
263 7 V263I,
359 11 A359T, p.A359PfsX12,
370 11 T370M,
923 15
1631 14 G1631D,
368 10
899 14
268 11 G268S,
252 15
257 6
400 9 G400E, G400R, G400A,