SCN5A Variant L812Q Detail

We estimate the penetrance of LQTS for SCN5A L812Q around 11% and the Brugada syndrome penetrance around 46%. SCN5A L812Q was found in a total of 1 carriers in 1 papers and/or in gnomAD: 1 had Brugada syndrome, 0 had LQTS. L812Q is not present in gnomAD. L812Q 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 (4 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 L812Q around 11% (0/11) and the Brugada syndrome penetrance around 46% (5/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-5.93 0.939 -3.61 0.974 54 15
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
26279430 2015 1 0 1 0
LITERATURE, COHORT, AND GNOMAD: - 1 0 0 1 -
VARIANT FEATURES ALONE: - 15 11 0 4 - -
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)
26279430 2015 HEK 40 -0.33 -19.7

L812Q has 59 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 13
811 7 c.2435_2436+3delTGGTAinsCGCCT, R811H, R811G,
733 13 F733L,
808 9 R808C, R808P, R808H,
1352 10
1453 14
1351 7 M1351V, M1351R,
760 14 p.F760SfsX5,
1449 12 Y1449S, Y1449C,
1452 13
812 0 L812Q,
1350 7 I1350L, I1350T,
792 12
791 11 L791F,
1344 11 F1344S, F1344L,
731 9 T731I,
806 11 V806M,
819 13
818 11
1353 11 V1353M,
737 11
1348 9 F1348L,
1349 9
749 15
788 10 I788V,
1346 9 L1346I, L1346P,
805 13 S805L,
1356 15 c.4066_4068delTT,
728 13 V728I,
810 7
727 11
735 11 A735V, A735E, A735T,
1456 14
732 13
734 7 M734V, c.2201dupT,
756 14
814 7 R814Q,
807 11
816 7 F816Y, F816L,
813 5 c.2437-5C>A, c.2436+12G>A,
757 14
1354 9
817 12 K817E,
1405 13 V1405M, V1405L,
809 6
815 6
1343 11
1345 14 W1345C,
1342 14
784 12 F784L,
736 14 L736P,
785 14 D785N,
730 10 N730K,
789 14 V789A, V789I,
753 12
1347 6
729 14 p.L729del,
795 12
787 13