ClinVar Genomic variation as it relates to human health

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. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on PTEN function (PMID: 29785012). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt PTEN protein function. ClinVar contains an entry for this variant (Variation ID: 490114). This variant has not been reported in the literature in individuals affected with PTEN-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 209 of the PTEN protein (p.Gly209Arg).

The p.G209R variant (also known as c.625G>A), located in coding exon 6 of the PTEN gene, results from a G to A substitution at nucleotide position 625. The glycine at codon 209 is replaced by arginine, an amino acid with dissimilar properties. This alteration has not been reported in 7051 unselected breast cancer patients and with a allele frequency of 0.00036 in 11241 female controls of Japanese ancestry (Momozawa Y et al. Nat Commun, 2018 10;9:4083). In a massively parallel functional assay using a humanized yeast model, lipid phosphatase activity for this variant was functionally neutral (Mighell TL et al. Am J Hum Genet, 2018 May;102:943-955). This variant also demonstrated wild type-like intracellular protein abundance in a massively parallel functional assay (Matreyek KA et al. Nat Genet, 2018 Jun;50:874-882). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Each variant was annotated with functional scores from MAVE data which was translated into functional evidence codes. All other evidence codes and combining criteria were adhered to as closely as possible based on the ClinGen VCEP (Variant Curation Expert Panel) gene-specific recommendations. See Supplemental Figure 34 of final paper (Supp Fig. 28 in preprint: doi:10.1101/2024.04.11.24305690) for a table to see which lines of evidence we did not have data for. The ClinGen VCEPs are highly regarded as the gold-standard for gene-specific variant curation and are developed after extensive evaluation of the evidence by clinical and scientific experts for the particular gene to classify genomic variants on a spectrum from pathogenic to benign using the 2015 ACMG/AMP Variant Interpretation Guidelines as a backbone (PMID: 25741868). Reclassification of these VUS variants from gnomAD or All of Us focused only on variants originally prescribed as VUS in ClinVar. To ensure reproducibility, transparency, and increased throughput, all the procedures for annotating variants and assigning evidence codes were codified using Python. All code has been made freely available and is linked in the Code Availability section and all reclassified variants with evidence codes used can be found in Tables S18-19 (preprint: doi:10.1101/2024.04.11.24305690). For the MAVE data, the clinical curation and clinical strength assignment as per the ClinGen recommendations in Brnich et al. (2020) (PMID: 31892348) for or against pathogenicity or benignity of each of these MAVE datasets utilized in this study were previously published in Fayer et al. (2021) (PMID: 34793697).For PTEN, two assays measuring activity and abundance were used. If the abundance was categorized as "wt-like" or "possibly wt-like," BS3_Supporting evidence was used. Furthermore, if the cumulative score was greater than -5, BS3_moderate evidence was used. This variant GRCh38:10:87952250:G>A was assigned evidence codes ['BS3_Supporting', 'BS1_Supporting'] and an overall classification of Likely benign