SCN5A Variant c.4299_4300insG Detail

We estimate the penetrance of LQTS for SCN5A c.4299_4300insG around 8% and the Brugada syndrome penetrance around 55%. SCN5A c.4299_4300insG was found in a total of 1 carriers in 1 papers and/or in gnomAD: 1 had Brugada syndrome, 0 had LQTS. c.4299_4300insG is not present in gnomAD. c.4299_4300insG has been functionally characterized in 1 papers. This residue is located in a 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 (5 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 c.4299_4300insG around 8% (0/11) and the Brugada syndrome penetrance around 55% (6/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA None 76 10
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
17905336 2007 1 0 1 0
LITERATURE, COHORT, AND GNOMAD: - 1 0 0 1 -
VARIANT FEATURES ALONE: - 15 10 0 5 - -
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)
17905336 2007

c.4299_4300insG has 49 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
1355 8
1403 10
1357 6 A1357V,
741 11 p.M741_T742delinsI ,
1430 12 D1430N,
808 13 R808H, R808P, R808C,
1352 11
1361 10
746 14 E746K,
1351 14 M1351V, M1351R,
739 9
1395 12
1397 13 c.4190delA, c.4189delT,
1350 15 I1350T, I1350L,
1429 13
1442 14 Y1442N, Y1442C,
806 15 V806M,
1398 14 V1398M,
1353 10 V1353M,
737 12
1358 5 G1358R, G1358W,
1362 13 R1362S, c.4083delG,
1433 4 G1433R, G1433W, G1433V,
1438 11 P1438L,
1388 12
1404 14
1387 14 L1387F,
1437 12
1431 8 S1431C,
805 12 S805L,
1359 5 K1359M, K1359N,
1356 8 c.4066_4068delTT,
1434 0 c.4299+1delG, c.4299G>A, c.4300-1G>A, c.4299delG, c.4300-2A>T, c.4299_4300insG, Y1434X, c.4299+28C>T, c.4299+1G>T, c.4299+2T>A,
1435 6
1360 10 F1360C,
1401 13
1354 10
1427 13 A1427S, A1427E,
1446 13
738 12
1432 9 R1432S, R1432G,
1389 14
1439 14 Q1439H, Q1439R,
740 11 p.N740del,
1443 12 N1443S,
1428 12 A1428S, A1428V,
804 15
1436 8
1402 12