rs55986646
Variant summary
Our verdict is Benign. Variant got -13 ACMG points: 0P and 13B. BP4_StrongBP6_Very_StrongBP7
The NM_000059.4(BRCA2):c.1644G>A(p.Gln548Gln) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000502 in 1,614,046 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★★).
Frequency
Consequence
NM_000059.4 synonymous
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -13 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
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BRCA2 | ENST00000380152.8 | c.1644G>A | p.Gln548Gln | synonymous_variant | Exon 10 of 27 | 5 | NM_000059.4 | ENSP00000369497.3 | ||
BRCA2 | ENST00000530893.7 | c.1275G>A | p.Gln425Gln | synonymous_variant | Exon 10 of 27 | 1 | ENSP00000499438.2 | |||
BRCA2 | ENST00000614259.2 | n.1644G>A | non_coding_transcript_exon_variant | Exon 9 of 26 | 2 | ENSP00000506251.1 |
Frequencies
GnomAD3 genomes AF: 0.0000723 AC: 11AN: 152204Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.000247 AC: 62AN: 251082Hom.: 0 AF XY: 0.000221 AC XY: 30AN XY: 135714
GnomAD4 exome AF: 0.0000479 AC: 70AN: 1461724Hom.: 0 Cov.: 35 AF XY: 0.0000440 AC XY: 32AN XY: 727152
GnomAD4 genome AF: 0.0000722 AC: 11AN: 152322Hom.: 0 Cov.: 32 AF XY: 0.0000940 AC XY: 7AN XY: 74486
ClinVar
Submissions by phenotype
Breast-ovarian cancer, familial, susceptibility to, 2 Benign:4
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The BRCA2 p.Gln548Gln variant was identified in the literature in one Chinese family with hereditary breast and ovarian cancer (Thirthagiri 2008); however, control chromosomes from healthy individuals were not evaluated in this study. The variant was also identified in dbSNP (ID: rs rs55986646) “With likely benign allele”, in the 1000 Genomes Project, in 1 of 5000 chromosomes (frequency 0.0002). It was also identified in the Exome Aggregation Consortium (ExAC) database (January 13, 2015) in 28 of 121014 chromosomes (frequency: 0.0002) (or 28 individuals from a population of 8644 East Asian individuals (frequency: 0.003)), and not from European (Non-Finnish)/African/Latino/South Asian/European (Finnish) or other individuals; the Clinvitae database classified the variant as benign/likely benign; ClinVar (4X, classified as a benign by BIC and GeneDX; likely benign by Ambry Genetics), and UMD (2X as a 3-unclassified variant variant, co-occurring with a pathogenic BRCA2 variant (c.1212delT (p.Asn404LysfsX26), increasing the likelihood that the p.Gln548Gln variant does not have clinical significance). The variant was also identified by our laboratory in 3 individuals with breast, and ovarian cancer including one with a co-occurring pathogenic variant (BRCA2 c.246delA), increasing the likelihood the p.Gln548Gln variant does not have clinical significance. The p.Gln548Gln variant is not expected to have clinical significance because it does not result in a change of amino acid and is not located in a known consensus splice site. However, four out of five in-silico splicing tools predict abolishment of a 3’ splice site in a region not expected to be involved in splicing, but this information is not very predictive of pathogenicity. In summary, based on the above information, this variant meets our laboratories criteria to be classified as benign. -
Synonymous substitution variant, with low bioinformatic likelihood to alter mRNA splicing (splicing prior 0.02; http://priors.hci.utah.edu/PRIORS/) and frequency 0.0032 (East Asian), derived from ExAC (2014-12-17). -
Hereditary cancer-predisposing syndrome Benign:3
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. -
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not specified Benign:2
Variant summary: BRCA2 c.1644G>A alters a non-conserved nucleotide resulting in a synonymous change. 5/5 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00024 in 274202 control chromosomes, predominantly at a frequency of 0.0034 within the East Asian subpopulation in the gnomAD database. The observed variant frequency within East Asian control individuals in the gnomAD database is approximately 5 fold of the estimated maximal expected allele frequency for a pathogenic variant in BRCA2 causing Hereditary Breast and Ovarian Cancer phenotype (0.00075), strongly suggesting that the variant is a benign polymorphism found primarily in populations of East Asian origin. c.1644G>A has been reported in the literature in individuals with personal and/or family history of Hereditary Breast and Ovarian Cancer (Hwang_2017, Trujillano_2015, Thirthagiri_2008, Suter_2004). These reports do not provide unequivocal conclusions about association of the variant with Hereditary Breast and Ovarian Cancer. Co-occurrences with a pathogenic variant have been reported (BRCA2 c.1212delT, p.Asn404Lysfs*26; UMD), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Four ClinVar submitters including an expert panel (ENIGMA) (evaluation after 2014) cite the variant as benign. Based on the evidence outlined above, the variant was classified as benign. -
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BRCA2-related disorder Benign:1
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
not provided Benign:1
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Hereditary breast ovarian cancer syndrome Benign:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at