ClinVar Genomic variation as it relates to human health

This variant is associated with the following publications: (PMID: 32123317, 31131967, 30995915, 28726806, 25348012, 26941049, 22476429, 17679929, 24504028, 25111659)

Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673).

Variant summary: BRCA2 c.3073A>G (p.Lys1025Glu) results in a conservative amino acid change located in the BRCA2 repeat (IPR002093) of the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4.8e-05 in 250060 control chromosomes, predominantly at a frequency of 9.7e-05 within the Non-Finnish European subpopulation in the gnomAD database. This frequency is not significantly higher than estimated for a pathogenic variant in BRCA2 causing Hereditary Breast And Ovarian Cancer Syndrome (4.8e-05 vs 0.00075), allowing no conclusion about variant significance. Multiple publications (Cunningham_2014, Lu_2012, Maier _2014, dosSantosVidal_2016) have cited c.3073A>G variant in affected individuals. In particular, one study, Yacoub_2007, cites the variant to occur in a man diagnosed with prostate cancer, whose daughter was diagnosed with breast cancer but did not carry the variant of interest, therefore, indicating the variant does not segregate with disease. Co-occurrences with other pathogenic variant(s) have been reported (BRCA1 c.1360_1361del, (p.Glu453_Ser454insTer), providing supporting evidence for a benign role (internal data). The following publications have been ascertained in the context of this evaluation (PMID: 24504028, 22476429, 25111659, 25348012, 17679929, 26941049, 34178674, 32599251). Ten submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as VUS (n=4) or benign/likely benign (n=6). Based on the evidence outlined above, the variant was classified as likely benign.

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

According to the ClinGen ENIGMA BRCA2 v1.1.0 criteria we chose these criteria: BP1 (strong benign): missense variants outside a (potentially) clinically important functional domain AND no splicing predicted (SpliceAI ≤0.1)., BS1 (supporting benign): (FAF) is above 0.002% (FAF > 0.00002) and less than or equal to 0.01% (FAF ≤ 0.0001) in gnomAD v2.1 (non-cancer, exome only subset) and/or gnomAD v3.1 (non-cancer)

The p.Lys1025Glu variant has been reported as a variant of unknown significance in the BIC (x5) and UMD (x2) databases. It has also been reported once in the literaure in a case report of male breast cancer in a patient receiving leuprolide therapy for prostate cancer (Yacoub_2007_17679929). It has not been previously identified by our laboratory. In addition, the variant is listed in the dbSNP database (ID#:rs80358550) as coming from a "clinical source" but no frequency information was provided, and so the prevalence of this variant in the population is not known. This residue is not conserved in mammals and computational analyses (PolyPhen2, SIFT, AlignGVGD) do not suggest a high likelihood of impact to the protein. However, this information is not predictive enough to rule out pathogenicity. In summary, based on the above information, the clinical significance of this variant cannot be determined at this time. This variant is classified as a variant of unknown significance.