SCN5A Variant I1948T Detail

We estimate the penetrance of LQTS for SCN5A I1948T around 12% and the Brugada syndrome penetrance around 7%. SCN5A I1948T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1948T is not present in gnomAD. I1948T has been functionally characterized in 0 papers. This residue is located in a Non_Hotspot region for Brugada syndrome and a Mild_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 (0 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A I1948T around 12% (0/10) and the Brugada syndrome penetrance around 7% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.771 0 13
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 15 0 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.

I1948T 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
1933 15 G1933V, G1933D, G1933A,
1934 14
1935 14 G1935S,
1936 13
1937 13 S1937A,
1938 12 E1938K, E1938X,
1939 11 p.E1939_E1943del,
1940 11
1941 10
1942 9 P1942S, P1942H,
1943 8
1944 8 R1944X, R1944Q,
1945 7
1946 5
1947 4
1948 0 I1948V,
1949 4 A1949T, A1949S,
1950 5 Y1950C,
1951 7 V1951M, V1951L,
1952 8
1953 8 p.S1953RfsX84,
1954 9 E1954K,
1955 10 N1955Y,
1956 11
1957 11 S1957P,
1958 12 R1958P, R1958Q, R1958X,
1959 13
1960 13
1961 14
1962 14 P1962S, P1962L,
1963 15 P1963L,