ClinVar Genomic variation as it relates to human health

The p.R428C variant (also known as c.1282C>T), located in coding exon 5 of the TGFBR2 gene, results from a C to T substitution at nucleotide position 1282. The arginine at codon 428 is replaced by cysteine, an amino acid with highly dissimilar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6,503 samples (13,006 alleles) with coverage at this position. This amino acid position is well conserved in available vertebrate species, except for three species. In addition, this alteration is predicted to be benign<span style="background-color: initial;">by PolyPhen but<span style="background-color: initial;">deleterious by SIFT <em style="background-color: initial;">in silico<span style="background-color: initial;"> analyses.<span style="background-color: initial;">Since supporting evidence is limited at this time, the clinical significance of this variant remains unclear.

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 403 of the TGFBR2 protein (p.Arg403Cys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TGFBR2-related conditions. ClinVar contains an entry for this variant (Variation ID: 263867). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C15"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Has not been previously published as pathogenic or benign to our knowledge; Not observed in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Reported in ClinVar as a variant of uncertain significance (ClinVar Variant ID# 263867; Landrum et al., 2016)

This missense variant replaces arginine with cysteine at codon 403 of the TGFBR2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with TGFBR2-related disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance.

Variant of Uncertain Significance due to insufficient evidence: This missense variant replaces arginine with cysteine at codon 428 of the TGFBR2 protein. Computational prediction tools and conservation analyses are inconclusive regarding the impact of this variant on the protein function. Computational splicing tools suggest that this variant may not impact RNA splicing. To our knowledge, functional assays have not been performed for this variant nor has this variant been reported in individuals affected with cardiovascular disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Available evidence is insufficient to determine the role of this variant in disease conclusively.