SCN5A Variant Q1909R Detail

We estimate the penetrance of LQTS for SCN5A Q1909R around 47% and the Brugada syndrome penetrance around 8%. SCN5A Q1909R was found in a total of 1 carriers in 3 papers and/or in gnomAD: 0 had Brugada syndrome, 1 had LQTS. Q1909R is not present in gnomAD. Q1909R has been functionally characterized in 6 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 (0 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 Q1909R around 47% (2/11) and the Brugada syndrome penetrance around 8% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-3.7 1 -0.27 0.987 1 50
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
25904541 2015 1 1 0 0
25757662 2015 1 0 0 1 SIDS
15840476 2005 1 1 0 0
LITERATURE, COHORT, AND GNOMAD: - 1 0 1 0 -
VARIANT FEATURES ALONE: - 15 14 1 0 - -
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)
28087622 2017 HEK 90 -3.3 -5.6 222
15840476 2005
25370050 2014 HEK 8.5 2.4
28734073 2017 HEK
25757662 2015 HEK 81 -8 -0.6 202
25904541 2015 HEK 58 4 7 371

Q1909R has 31 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
1894 15
1895 14 T1895I,
1896 14 L1896P, p.L1896PfsX47,
1897 13 R1897Y, R1897W, R1897Q,
1898 13 R1898C, R1898H,
1899 12
1900 11
1901 11 E1901K, E1901Q,
1902 10 E1902A,
1903 9 V1903M,
1904 8 S1904L,
1905 8
1906 7 M1906V, M1906T,
1907 5
1908 4 I1908V,
1909 0 Q1909R,
1910 4 R1910K,
1911 5
1912 7
1913 8 R1913C, R1913S, R1913H,
1914 8 R1914G,
1915 9 H1915Q, H1915N, H1915P, H1915Y,
1916 10
1917 11
1918 11
1919 12 R1919C, R1919H,
1920 13 S1920C,
1921 13
1922 14 K1922R, K1922N,
1923 14 H1923Y, H1923D,
1924 15 A1924T,