SCN5A Variant Q750H Detail

We estimate the penetrance of LQTS for SCN5A Q750H around 38% and the Brugada syndrome penetrance around 11%. SCN5A Q750H was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. Q750H is not present in gnomAD. Q750H has been functionally characterized in 0 papers. This residue is located in a Non_Hotspot region for Brugada syndrome and a 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 Q750H around 38% (1/10) and the Brugada syndrome penetrance around 11% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.629 8 51
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.

Q750H has 42 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
758 13 G758E,
742 13 T742A,
811 10 R811H, R811G, c.2435_2436+3delTGGTAinsCGCCT,
733 10 F733L,
741 11 p.M741_T742delinsI ,
808 10 R808P, R808H, R808C,
745 11
746 8 E746K,
760 15 p.F760SfsX5,
759 14 c.2274delG, I759V, p.I759FfsX6,
792 12
755 9
800 10 R800C, R800H, R800L,
754 6
797 12 G797V,
737 11
750 0 Q750R,
749 6
743 11
798 14
793 14 L793F,
747 6 E747A,
735 14 A735E, A735T, A735V,
732 15
734 12 c.2201dupT, M734V,
756 11
814 14 R814Q,
807 15
757 10
1354 14
744 12
752 6 G752R,
751 5 V751F, V751I,
796 9
802 14
736 13 L736P,
730 12 N730K,
753 5
729 15 p.L729del,
795 10
748 8 M748I,
799 9