Description
The BRCA2 p.Val2739Ile variant was identified in 10 of 3474 proband chromosomes (frequency: 0.003) from Australian, Polish, German and Hawaiian individuals or families with triple negative breast cancer or HBOC (Wong-Brown 2015 25682074, Lai 2015, Hondow 2011 21702907, Carney 2010 21218378, Trujillano 2015 25556971, Bosdet 2013 24094589). In a computational method that produces a probabilistic likelihood ratio predictive of impaired protein function, the variant was found to be neutral consistent with previously reported functional data related to homology directed repair (Karchin 2008). The variant was also identified in dbSNP (ID: rs80359069) “With Likely benign, Uncertain significance, other allele”, ClinVar (classified benign by Invitae, likely benign by Ambry Genetics, GeneDx, Quest Diagnostics Nichols Institute San Juan Capistrano, and uncertain significance by Laboratory Corporation of America, SCRP and BIC), Clinvitae (5x), LOVD 3.0 (10x as predicted neutral and unknown function), UMD-LSDB (13x unclassified), BIC Database (6x unknown clinical importance, classification pending), and was not identified in Cosmic, MutDB, ARUP Laboratories, or the Zhejiang Colon Cancer Database. The variant was identified in control databases in 2 of 244404 chromosomes at a frequency of 0.000008 (Genome Aggregation Database Feb 27, 2017), in the East Asian population in 2 of 17246 chromosomes (freq: 0.0001), while not observed in the African, Other, Latino, European Non-Finnish, Ashkenazi Jewish, European Finnish and South Asian populations. The p.Val2739 residue is not conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood of the p.Val2739Ile variant impacting the protein; however, this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time although we would lean towards a more benign role for this variant. This variant is classified as likely benign.
# | Sample | Method | Observation |
---|
Origin | Affected | Number tested | Tissue | Purpose | Method | Individuals | Allele frequency | Families | Co-occurrences |
---|
1 | unknown | yes | not provided | not provided | not provided | | not provided | not provided | not provided | not provided |