SCN5A Variant Y1977F Detail

We estimate the penetrance of LQTS for SCN5A Y1977F around 48% and the Brugada syndrome penetrance around 9%. SCN5A Y1977F was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. Y1977F is not present in gnomAD. Y1977F has been functionally characterized in 1 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 (2 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A Y1977F around 48% (2/10) and the Brugada syndrome penetrance around 9% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-3.65 0.983 0.28 0.651 0 60
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 2 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)
29734505 2018 HEK -2 -0.3

Y1977F 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
1962 15 P1962L, P1962S,
1963 14 P1963L,
1964 14 S1964F,
1965 13 S1965N, S1965G,
1966 13
1967 12 p.S1967LfsX12,
1968 11 I1968N, I1968T, I1968M, I1968V, I1968S,
1969 11
1970 10 p.S1970_S1972del,
1971 9
1972 8
1973 8 F1973L,
1974 7
1975 5 P1975T,
1976 4 S1976C,
1977 0 Y1977N,
1978 4
1979 5
1980 7 V1980F,
1981 8
1982 8 R1982T,
1983 9 A1983V, A1983G,
1984 10 T1984I,
1985 11 S1985R,
1986 11 D1986G, D1986N,
1987 12 N1987K,
1988 13 L1988R,
1989 13
1990 14 V1990L,
1991 14 R1991W, R1991Q,
1992 15 G1992A,