--- title: "BRCA1 M1663Cfs*14 (c.4987del, rs886040912) | Dante Labs" description: "ClinVar classifies BRCA1 M1663Cfs*14 as Pathogenic (reviewed by expert panel). Where it sits in the genome, its predicted effect, and the Genome Test reports that look at it." url: "https://dantelabs.com/genes/brca1/variants/m1663cfs14" --- 1. [Genes](https://dantelabs.com/genes) 2. [BRCA1](https://dantelabs.com/genes/brca1) 3. BRCA1 M1663Cfs\*14 Variant # BRCA1 M1663Cfs\*14 NM_007294.4(BRCA1):c.4987del (p.Met1663CysfsTer14) Also known as - p.Met1663CysfsTer14 - p.M1663Cfs\*14 - rs886040912 * ClinVar classification Pathogenic * Review status 3 stars out of 4 reviewed by expert panel * Last evaluated 15 December 2017 * Expert panel Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) Data current to ClinVar release 2026-10-12 · Dante Labs data release 2026.10.16-c6eea6bf Facts last changed 16 October 2026 ## Summary M1663Cfs\*14 is a frameshift variant in BRCA1: it adds or removes DNA letters in a way that shifts how the rest of the gene's code is read. ClinVar classifies it as pathogenic for breast-ovarian cancer, familial, susceptibility to, 1 (reviewed by expert panel). ## ClinVar classifications | Condition | Classification | Review status | Submissions | Last evaluated | | -------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | ----------------------------------------- | ------------ | ---------------- | | breast-ovarian cancer, familial, susceptibility to, 1[ClinVar VCV000267569 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/clinvar/variation/267569/) | Pathogenic | 3 stars out of 4 reviewed by expert panel | 1 submission | 15 December 2017 | Classifications as ClinVar records them in release 2026-10-12. ClinVar updates them as evidence is reviewed. ## Where it lies in BRCA1 M1663Cfs\*14 lies in exon 16 of the 23 in BRCA1's MANE Select transcript, NM_007294.4. [BRCA1 variants in exon 16 →](https://dantelabs.com/genes/brca1/variants?exon=16) [BRCA1's gene diagram →](https://dantelabs.com/genes/brca1#gene-structure) ## Molecular details | Gene | [BRCA1](https://dantelabs.com/genes/brca1) | | --------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Transcript | NM_007294.4 MANE Select | | Coding DNA change (HGVS c.) | c.4987del | | Protein change (HGVS p.) | p.Met1663CysfsTer14 p.M1663Cfs\*14 | | Predicted consequence | Frameshift [frameshift_variant (opens in a new tab)](https://purl.obolibrary.org/obo/SO_0001589) [frameshift_truncation (opens in a new tab)](https://purl.obolibrary.org/obo/SO_0001910) [exonic_splice_region_variant (opens in a new tab)](https://purl.obolibrary.org/obo/SO_0002084) | | Predicted impact | High | | Position (GRCh38) | chr17:43067694 AT>A | | Position (GRCh37) | chr17:41219711 AT>A | | dbSNP ID | [rs886040912 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/snp/rs886040912) | | ClinVar Variation ID | [VCV000267569 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/clinvar/variation/267569/) | | ClinVar Allele ID | 262944 | | ClinGen Allele Registry ID | [CA10602583 (opens in a new tab)](https://reg.clinicalgenome.org/redmine/projects/registry/genboree_registry/by_canonicalid?canonicalid=CA10602583) | | ClinVar name | NM_007294.4(BRCA1):c.4987del (p.Met1663fs) | ## BRCA1 M1663Cfs\*14 in other databases - [ClinVar VCV000267569 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/clinvar/variation/267569/) - [dbSNP rs886040912 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/snp/rs886040912) - [ClinGen Allele Registry CA10602583 (opens in a new tab)](https://reg.clinicalgenome.org/redmine/projects/registry/genboree_registry/by_canonicalid?canonicalid=CA10602583) - [gnomAD 17-43067694-AT-A (opens in a new tab)](https://gnomad.broadinstitute.org/variant/17-43067694-AT-A?dataset=gnomad_r4) - [Ensembl rs886040912 (opens in a new tab)](https://www.ensembl.org/Homo_sapiens/Variation/Explore?v=rs886040912) ## Reports that look at this variant (1) These Genome Test condition reports include M1663Cfs\*14 among the variants they look at. | Report | Conditions | Inheritance | | ------------------------------------------------------------------------------------------------------------------- | --------------------------------------------- | ------------------ | | [Hereditary Breast and Ovarian Cancer (BRCA1/2)](https://dantelabs.com/conditions/hereditary-breast-ovarian-cancer) | Hereditary Breast and Ovarian Cancer Syndrome | Autosomal dominant | | | BRCA1-related cancer predisposition | Autosomal dominant | ## Other variants in BRCA1 - [A92Ffs\*4 Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a92ffs4) - [A134Qfs\*7 Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a134qfs7) - [A302Cfs\*2 Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a302cfs2) - [A302Lfs\*12 Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a302lfs12) - [A322Kfs\*2 Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a322kfs2) - [A322Lfs\*19 Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a322lfs19) - [A407Sfs\*5 Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a407sfs5) - [A433Pfs\*8 Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a433pfs8) - [A469Qfs\*6 Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a469qfs6) - [A521X Pathogenic 3 stars out of 4](https://dantelabs.com/genes/brca1/variants/a521x) [All BRCA1 variants](https://dantelabs.com/genes/brca1/variants) ## Limitations This page describes publicly available information about a genetic variant. It is not a diagnosis, and it says nothing about whether you or anyone else carries this variant. Classifications come from ClinVar and change as new evidence is reviewed. A classification here may differ from the one in ClinVar today, or from the one a laboratory reports. Whole genome sequencing with short reads can miss or miscall some variants, particularly in repeated or highly similar stretches of DNA and in large insertions, deletions or rearrangements. If you have questions about a variant in your own results or in your family, talk to a genetic counsellor or your doctor. ## Sources & credits - Classifications from ClinVar (release 2026-10-12), National Center for Biotechnology Information. - Condition terms from the Mondo Disease Ontology (release 2026-10-06), used under CC BY 4.0. - Gene symbols and names from the HUGO Gene Nomenclature Committee (release 2026-10-16). - Allele identifiers from the ClinGen Allele Registry (release 2026-10-16-c4908f54). - Reference SNP identifiers from dbSNP (release b157), National Center for Biotechnology Information. - Gene–disease links from the Gene Curation Coalition, GenCC (release 2026-10-16). - Difficult regions from the Genome in a Bottle Consortium (release v3.6). - Transcripts from MANE (release v1.5), NCBI and EMBL-EBI. - Predicted consequences from mehari (release 0.11.0), with transcript models from cdot. - Built from Dante Labs data release 2026.10.16-c6eea6bf of 16 October 2026. ## Cite this page APA > Dante Labs. (16 October 2026). BRCA1 M1663Cfs\*14 (c.4987del, rs886040912) (Version 2026.10.16-c6eea6bf). Retrieved 17 October 2026, from https\://dantelabs.com/genes/brca1/variants/m1663cfs14 Vancouver > Dante Labs. BRCA1 M1663Cfs\*14 (c.4987del, rs886040912) \[Internet]. Version 2026.10.16-c6eea6bf. 16 October 2026 \[cited 17 October 2026]. Available from: https\://dantelabs.com/genes/brca1/variants/m1663cfs14 Download citation [RIS](https://dantelabs.com/genes/brca1/variants/m1663cfs14/cite.ris) [BibTeX](https://dantelabs.com/genes/brca1/variants/m1663cfs14/cite.bib) [CSL-JSON](https://dantelabs.com/genes/brca1/variants/m1663cfs14/cite.json) ## Read your whole genome From $449 Free shipping · Results in 6–8 weeks [Explore the Genome Test](https://dantelabs.com/whole-genome-sequencing)