SCN5A Variant L749P Detail

We estimate the penetrance of LQTS for SCN5A L749P around 20% and the Brugada syndrome penetrance around 15%. SCN5A L749P was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L749P is not present in gnomAD. L749P has been functionally characterized in 0 papers. This residue is located in a Mild_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 (1 diagnosed with Brugada syndrome) and 5 individuals for LQTS (1 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A L749P around 20% (1/10) and the Brugada syndrome penetrance around 15% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.978 11 24
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 1 1 - -
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.

L749P has 45 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
1357 15 A1357V,
742 10 T742A,
811 10 R811H, c.2435_2436+3delTGGTAinsCGCCT, R811G,
733 6 F733L,
741 8 p.M741_T742delinsI ,
808 11 R808P, R808C, R808H,
745 7
746 7 E746K,
739 14
812 15 L812Q,
1350 13 I1350T, I1350L,
755 11
731 11 T731I,
754 10
726 14
1353 13 V1353M,
737 7
1404 15
750 6 Q750R,
749 0
743 10
728 14 V728I,
747 7 E747A,
727 15
735 9 A735V, A735T, A735E,
732 10
734 8 M734V, c.2201dupT,
756 10
814 14 R814Q,
757 13
1354 12
744 10
738 11
752 6 G752R,
1405 14 V1405M, V1405L,
740 13 p.N740del,
751 7 V751I, V751F,
796 13
736 7 L736P,
730 9 N730K,
753 6
729 11 p.L729del,
795 13
748 4 M748I,
799 14