SCN5A Variant I267L Detail

We estimate the penetrance of LQTS for SCN5A I267L around 8% and the Brugada syndrome penetrance around 9%. SCN5A I267L was found in a total of 0 carriers in 1 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I267L is not present in gnomAD. I267L has been functionally characterized in 1 papers. This residue is located in a Non_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 (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 I267L around 8% (0/10) and the Brugada syndrome penetrance around 9% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-1.95 0.437 2.47 0.802 7 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
22677073 2012 1 0 0 1 SUDS
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.

Functional Data

Peak and late/persistent current are relative to wildtype (100% being no different from wildtype). V0.5 act/inact are the voltages at which half of the maximal current is reached during an activation and inactivation protocol, each is in units of mV and relative to wildtype.
PubMed ID Year Cell Type Peak Current (%WT) V1/2 Act. (mV) V1/2 Inact. (mV) Late/Persistent Current (%WT)
22677073 2012

I267L has 73 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 12
271 6 L271V,
266 5 L266H,
276 14 L276P, L276Q,
363 15
1544 14 T1544P,
270 6 Q270K,
1627 6
396 9 V396A, V396L,
385 14 A385T,
1624 7 V1624I,
355 9 F355I, F355C,
1549 15
1538 14
391 11
388 14 I388S,
356 13 D356N,
1543 13 V1543L, V1543A,
1542 10
361 10
260 11
366 15
365 9
258 14 V258A,
354 13
1546 10 M1546T,
369 14 M369K,
1545 9
1630 11 I1630R, I1630V,
1626 11 R1626P, R1626C, R1626L, R1626H,
267 0
1625 11
262 9 S262G,
357 13
399 13
272 8
397 14 I397F, I397T, I397V,
274 14 G274C,
362 12
261 10
273 11
1628 10
1539 15 C1539Y, C1539F,
392 7
389 11 Y389H, Y389X,
269 7
1620 10 T1620M, T1620K,
395 9
393 11
394 13
390 15
275 13 N275K,
264 5
259 12
1548 12 E1548K, G1548K,
265 6 A265V,
1619 12 P1619Q, c.4856delC, P1619L,
358 10
263 6 V263I,
359 14 p.A359PfsX12, A359T,
1629 14 R1629Q, R1629X, R1629G,
1547 14 V1547L,
1541 13
381 13 c.1141-3C>A, c.1140+1G>A,
368 12
1631 14 G1631D,
268 4 G268S,
377 15
1622 12
1618 15
400 13 G400R, G400A, G400E,
1621 11
1623 8 c.4867delC, R1623X, R1623Q, R1623L,