SCN5A Variant M734I Detail

We estimate the penetrance of LQTS for SCN5A M734I around 8% and the Brugada syndrome penetrance around 52%. SCN5A M734I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. M734I is not present in gnomAD. M734I has been functionally characterized in 0 papers. This residue is located in a 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 (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 M734I around 8% (0/10) and the Brugada syndrome penetrance around 52% (5/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.915 79 6
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 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.

M734I 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
1355 14
1357 13 A1357V,
811 6 R811H, R811G, c.2435_2436+3delTGGTAinsCGCCT,
733 6 F733L,
741 13 p.M741_T742delinsI ,
808 9 R808P, R808H, R808C,
745 13
1352 11
1406 14 G1406R, G1406E,
746 14 E746K,
1351 10 M1351R, M1351V,
760 13 p.F760SfsX5,
812 7 L812Q,
1350 6 I1350L, I1350T,
792 13
755 14
791 15 L791F,
1344 15 F1344L, F1344S,
731 5 T731I,
806 15 V806M,
754 13
726 12
818 12
1353 9 V1353M,
737 7
1348 13 F1348L,
1404 13
750 12 Q750R,
1349 10
749 8
788 13 I788V,
1346 9 L1346P, L1346I,
805 15 S805L,
724 15 T724I,
728 10 V728I,
810 12
727 10
1408 14 G1408R,
735 5 A735E, A735T, A735V,
732 7
734 0 c.2201dupT, M734V,
756 10
814 8 R814Q,
807 14
816 12 F816L, F816Y,
813 11 c.2436+12G>A, c.2437-5C>A,
757 12
1354 9
817 14 K817E,
738 13
752 10 G752R,
1405 10 V1405M, V1405L,
809 10
815 8
1343 13
1342 14
751 13 V751F, V751I,
796 15
736 8 L736P,
730 5 N730K,
753 8
1347 9
729 10 p.L729del,
795 13
748 12 M748I,
1402 15