{{Rsnum
|rsid=1800709
|Gene=BRCA1
|Chromosome=17
|position=43093010
|Orientation=plus
|ReferenceAllele=C
|MissenseAllele=T
|GMAF=0.001377
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(C;C)
|geno2=(C;T)
|geno3=(T;T)
|Gene_s=BRCA1
}}{{ population diversity
| geno1=(C;C)
| geno2=(C;T)
| geno3=(T;T)
| CEU | 98.2 | 1.8 | 0.0
| HCB | 100.0 | 0.0 | 0.0
| JPT | 99.1 | 0.9 | 0.0
| YRI | 100.0 | 0.0 | 0.0
| ASW | 98.2 | 1.8 | 0.0
| CHB | 100.0 | 0.0 | 0.0
| CHD | 0.0 | 0.0 | 0.0
| GIH | 0.0 | 0.0 | 0.0
| LWK | 0.0 | 0.0 | 0.0
| MEX | 96.5 | 3.5 | 0.0
| MKK | 0.0 | 0.0 | 0.0
| TSI | 0.0 | 0.0 | 0.0
| HapMapRevision=28
}}[[rs41293463]] is a SNP causing an amino acid change in the breast cancer 1 [[BRCA1]] gene at amino position 841. The more common [[rs41293463]](C) allele encodes Arg, while the rare [[rs41293463]](T) allele encodes Trp; this SNP is also known as R841W.

A 1996 study of 305 cases in Southern California of [[breast cancer]] and [[ovarian cancer]] found 3 cases carrying the [[rs1800709]](T) allele. In all three cases, there was a strong family history of breast, ovarian, or other cancers, and family members showed a high concordance of cancer incidence with the presence of this SNP. However, the age of cancer onset was the same as for sporadic cases. The authors conclude that this SNP may explain around 1% (CI: 0-1.7%) of all breast and ovarian cancers, at least for this population. {{PMID|8968716}}

Note: this SNP is rather unlikely to be a causative or high penetrance mutation, given it's frequency in the population at large.

* See also [http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=113705&a=113705_AllelicVariant0022 Omim 113705.0022]

{{ neighbor
| rsid = 4986852
| distance = 598
}}

{{ neighbor
| rsid = 4986850
| distance = 444
}}

{{ neighbor
| rsid = 799917
| distance = 91
}}

{{omim
|id=113705
|rsnum=1800709
|variant=0022
}}

{{ClinVar
|rsid=1800709
|Reversed=1
|FwdREF=C
|FwdALT=T
|REF=G
|ALT=A
|RSPOS=41245027
|CHROM=17
|GMAF=0.0014
|dbSNPBuildID=89
|SSR=0
|SAO=1
|VP=0x050160000000040517110100
|GENEINFO=BRCA1:672
|GENE_NAME=BRCA1
|GENE_ID=672
|WGT=0
|VC=SNV
|CLNALLE=1
|CLNHGVS=NC_000017.10:g.41245027G>A
|CLNSRC=OMIM Allelic Variant
|CLNORIGIN=1
|CLNSRCID=113705.0022
|CLNSIG=255
|CLNCUI=C2676676
|CLNDBN=Breast-ovarian cancer, familial 1; not provided; Familial cancer of breast
|Disease=Breast-ovarian cancer; not provided; Familial cancer of breast
|CLNACC=RCV000019251.3; RCV000034733.1; RCV000047867.2
|Tags=RV;PM;SLO;VLD;HD;GNO;KGPhase1;KGPROD;OTHERKG;PH3;LSD;OM
|CAF=0.9986; 0.001377
|CLNDSDB=GeneReviews:MedGen:OMIM:Orphanet; GeneReviews:MedGen:OMIM:SNOMED_CT
|CLNDSDBID=NBK1247:C2676676:604370:145; NBK1247:C0346153:114480:254843006
|COMMON=0
}}

{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | FTDNA2}}
{{on chip | FTDNA}}
{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}