SCN5A Variant P1730H Detail

We estimate the penetrance of LQTS for SCN5A P1730H around 4% and the Brugada syndrome penetrance around 28%. SCN5A P1730H was found in a total of 5 carriers in 3 papers and/or in gnomAD: 2 had Brugada syndrome, 0 had LQTS. P1730H is not present in gnomAD. P1730H has been functionally characterized in 4 papers. This residue is located in a Mild_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 (2 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 P1730H around 4% (0/15) and the Brugada syndrome penetrance around 28% (4/15).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-6.72 1 -1.63 0.662 22 0
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
26036855 2016 2 0 2 0
28781330 2017 5 0 2 0
29325976 2018 1 0 1 0
LITERATURE, COHORT, AND GNOMAD: - 5 3 0 2 -
VARIANT FEATURES ALONE: - 15 13 0 2 - -
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)
28781330 2017
32533946 2020 HEK 45 6.7 7.3
29325976 2018
26036855 2016

P1730H has 23 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
1727 10
1739 10 R1739W, R1739Q,
1734 10
1737 12 G1737D,
1724 13
1741 11 D1741E, D1741N, D1741Y,
1731 4
1728 7 C1728Y, C1728R, C1728W,
1722 13 N1722D,
1744 15 S1744I,
1729 4 D1729N,
1726 12
1740 11 G1740R,
1742 9
1735 11
1733 7
1732 7
1736 14
1725 11 P1725L,
1743 12 G1743E, G1743R,
1730 0 P1730L, P1730A, P1730H,
1683 14
1738 10 S1738T, S1738F,