ClinVar Genomic variation as it relates to human health

Class 1 not pathogenic based on frequency >1% in an outbred sampleset. Frequency 0.02642 (African), derived from 1000 genomes (2012-04-30).

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease.

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease.

BRCA2: BP4, BS1, BS2

This alteration is classified as 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.

BA1 based on allele frequency in AFR of 0.0249 in gnomAD.

The BRCA2 p.Val3244Ile variant was identified in the literature in 5/7922 proband chromosomes (frequency: 0.001) from individuals with breast cancer; however, no control chromosomes were tested to establish the frequency of the variant in the general population (Borg 2010, Caux-Moncoutier 2011; Haffty 2009). The variant was also identified in the BIC database (73X with unknown clinical importance) and in UMD (28X as an unclassified variant) where it was listed to co-occur with a pathogenic mutation in BRCA1 (c.2551G>T (p.Glu851X)), increasing the likelihood that this variant may not have clinical importance. The p.Val3244 residue is not conserved in mammals, and the variant amino acid Isoleucine (Ile) is present in macaque at this position, increasing the likelihood that an alteration to this residue may not have functional significance. Computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM) do not predict any effect on the protein function; however, this information is not predictive enough to rule out pathogenicity. The variant is listed in dbSNP as coming from a "clinical source" (ID#: rs11571831) with a minor allele frequency of 0.006 (1000 Genomes). It was also identified in the NHLBI Exome Sequencing Project with a frequency of 0.025 in African American alleles, and in several HapMap populations including HapMap-YRI (frequency: 0.032), HapMap-JPT (frequency: 0.03) and HapMap-CEU (frequency: 0.033), increasing the likelihood that this is a low frequency benign polymorphism in certain populations of origin. In summary, based on the above information, this variant meets our laboratory's criteria to be classified as benign.