Breast Cancer 1 Gene

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OMIM Number




Uniprot ID



125,951 bases

No. of Exons


No. of isoforms


Protein Name

Breast cancer type 1 susceptibility protein

Molecular Mass

207721 Da

Amino Acid Count


Genomic Location


Gene Map Locus


BRCA1 is a tumor suppressor gene that plays an important role in transcription, DNA repair, and recombination. In conjunction with other elements involved in tumor suppression, signal transduction, and DNA repair, BRCA1 has a critical function towards maintaining genomic stability. Mutations in BRCA1 is implicated in different types of cancers including familial breast cancer, proliferative breast disease, ovarian cancer, peritoneal papillary serous carcinoma, and prostate cancer. It accounts for approximately 40% of inherited breast cancers and 80% of inherited breast and ovarian cancers.

Epidemiology in the Arab World

View Map
Variant NameCountryGenomic LocationClinvar Clinical SignificanceCTGA Clinical Significance Condition(s)HGVS ExpressionsdbSNPClinvar
NM_007294.3:c.441+18CTT[6]LebanonNC_000017.11:g.43104086GAA[6]BenignBreast CancerNG_005905.2:g.113880CTT[6]; NM_007294.3:c.441+18CTT[6]147856441225704
NM_007294.4:c.1067A>GLebanonchr17:43094464BenignAssociation, BenignBreast CancerNG_005905.2:g.123520A>G; NM_007294.4:c.1067A>G; NP_009225.1:p.Gln356Arg179995041803
NM_007294.4:c.1140dupYemenNC_000017.11:g.43094391dupPathogenicLikely PathogenicBreast-Ovarian Cancer, Familial, Susceptibility to, 1NG_005905.2:g.123593dup; NM_007294.4:c.1140dup; NP_009225.1:p.Lys381GlufsTer3876659327231732
NM_007294.4:c.1224delEgyptNC_000017.11:g.43094309delPathogenicLikely PathogenicBreast-Ovarian Cancer, Familial, Susceptibility to, 1NG_005905.2:g.123677del; NM_007294.4:c.1224del; NP_009225.1:p.Val409Ter879255320252436
NM_007294.4:c.1250A>GUnited Arab EmiratesNC_000017.11:g.43094281T>CBenign, Likely Benign, Uncertain SignificanceUncertain SignificanceBreast-Ovarian Cancer, Familial, Susceptibility to, 1NG_005905.2:g.123703A>G; NM_007294.4:c.1250A>G; NP_009225.1:p.Asn417Ser8035711354174
NM_007294.4:c.131G>TLebanonchr17:43115729PathogenicPathogenicBreast CancerNG_005905.2:g.102255G>T; NM_007294.4:c.131G>T; NP_009225.1:p.Cys44Phe8035744654200
NM_007294.4:c.1456T>CLebanonchr17:43094075BenignBenignBreast CancerNG_005905.2:g.123909T>C; NM_007294.4:c.1456T>C; NP_009225.1:p.Phe486Leu5590693154258
NM_007294.4:c.1648A>CLebanonchr17:43093883BenignBenignBreast CancerNG_005905.2:g.124101A>C; NM_007294.4:c.1648A>C; NP_009225.1:p.Asn550His5601264137423
NM_007294.4:c.1703C>TLebanonNC_000017.11:g.43093828G>ABenign, Likely Benign, Uncertain SignificanceUncertain SignificanceBreast CancerNG_005905.2:g.124156C>T; NM_007294.4:c.1703C>T; NP_009225.1:p.Pro568Leu8035691054329
NM_007294.4:c.1771A>GUnited Arab EmiratesNC_000017.11:g.43093760T>CBenign, Likely Benign, Uncertain SignificanceUncertain SignificanceProstate CancerNG_005905.2:g.124224A>G; NM_007294.4:c.1771A>G; NP_009225.1:p.Ile591Val1064795358421781
NM_007294.4:c.1772T>CLebanonNC_000017.11:g.43093759A>GLikely Benign, Uncertain SignificanceUncertain SignificanceBreast CancerNG_005905.2:g.124225T>C; NM_007294.4:c.1772T>C; NP_009225.1:p.Ile591Thr8035685954345
NM_007294.4:c.1845T>CLebanonNC_000017.11:g.43093686A>GLikely BenignBreast CancerNG_005905.2:g.124298T>C; NM_007294.4:c.1845T>C ; NP_009225.1:p.Ser615=13493146701551757
NM_007294.4:c.2077G>ALebanonchr17:43093454BenignBenignBreast CancerNG_005905.2:g.124530G>A; NM_007294.4:c.2077G>A; NP_009225.1:p.Asp693Asn498685041808
NM_007294.4:c.2082C>TLebanonchr17:43093449BenignBenignBreast CancerNG_005905.2:g.124535C>T; NM_007294.4:c.2082C>T; NP_009225.1:p.Ser694=1799949125536
NM_007294.4:c.213-45T>A Lebanonchr17:43105001Breast CancerNG_005905.2:g.112983T>A; NM_007294.4:c.213-45T>A2054702554
NM_007294.4:c.2158G>TLebanonNC_000017.11:g.43093373C>APathogenicPathogenicBreast CancerNG_005905.2:g.124611G>T; NM_007294.4:c.2158G>T; NP_009225.1:p.Glu720Ter8035687537453
NM_007294.4:c.2311T>CLebanonchr17:43093220BenignBenignBreast CancerNG_005905.2:g.124764T>C; NM_007294.4:c.2311T>C; NP_009225.1:p.Leu771=16940125554
NM_007294.4:c.2410_2411delLebanonNC_000017.11:g.43093120_43093121delPathogenicBreast CancerNG_005905.2:g.124863_124864del; NM_007294.4:c.2410_2411del; NP_009225.1:p.Gln804Valfs*5
NM_007294.4:c.2458A>GLebanonchr17:43093073BenignBenignBreast CancerNG_005905.2:g.124911A>G; NM_007294.4:c.2458A>G; NP_009225.1:p.Lys820Glu5608211341810
NM_007294.4:c.2612C>TLebanonchr17:43092919BenignBenignBreast CancerNG_005905.2:g.125065C>T; NM_007294.4:c.2612C>T; NP_009225.1:p.Pro871Leu79991741812
NM_007294.4:c.3113A>GLebanonchr17:43092418BenignBenignBreast CancerNG_005905.2:g.125566A>G; NM_007294.4:c.3113A>G; NP_009225.1:p.Glu1038Gly1694141815
NM_007294.4:c.3119G>ALebanonchr17:43092412BenignBenignBreast CancerNG_005905.2:g.125572G>A; NM_007294.4:c.3119G>A; NP_009225.1:p.Ser1040Asn498685217670
NM_007294.4:c.3228_3229delEgypt; United Arab Emi...NC_000017.11:g.43092304_43092305delPathogenicLikely PathogenicBreast-Ovarian Cancer, Familial, Susceptibility to, 1NG_005905.2:g.125679AG[1]; NM_007294.4:c.3228_3229del; NP_009225.1:p.Gly1077AlafsTer88035763537516
NM_007294.4:c.3367G>TLebanonNC_000017.11:g.43092164C>ALikely Benign, Uncertain SignificanceUncertain SignificanceBreast CancerNG_005905.2:g.125820G>T; NM_007294.4:c.3367G>T; NP_009225.1:p.Asp1123Tyr8035686754860
NM_007294.4:c.34C>TLebanonNC_000017.11:g.43124063G>APathogenic, Uncertain SignificancePathogenicBreast CancerNG_005905.2:g.93921C>T; NM_007294.4:c.34C>T; NP_009225.1:p.Gln12Ter8035713454902
NM_007294.4:c.3526G>ALebanonchr17:43092005Uncertain SignificanceBreast CancerNG_005905.2:g.125979G>A; NM_007294.4:c.3526G>A; NP_009225.1:p.Val1176Ile777796838565640
NM_007294.4:c.3548A>GLebanonchr17:43091983BenignBenignBreast CancerNG_005905.2:g.126001A>G; NM_007294.4:c.3548A>G; NP_009225.1:p.Lys1183Arg1694241818
NM_007294.4:c.4065_4068delEgypt; United Arab Emi...NC_000017.11:g.43091465_43091468delPathogenicLikely PathogenicBreast-Ovarian Cancer, Familial, Susceptibility to, 1NG_005905.2:g.126518_126521del; NM_007294.4:c.4065_4068del; NP_009225.1:p.Asn1355LysfsTer108035750817674
NM_007294.4:c.4096+106G>ALebanonchr17:43091329Breast CancerNG_005905.2:g.126655G>A; NM_007294.4:c.4096+106G>A
NM_007294.4:c.4132G>ALebanonNC_000017.11:g.43090997C>TBenign, Likely Benign, Uncertain SignificanceUncertain SignificanceBreast CancerNG_005905.2:g.126987G>A; NM_007294.4:c.4132G>A; NP_009225.1:p.Val1378Ile2889769055111
NM_007294.4:c.424C>GLebanonchr17:43104139Breast CancerNG_005905.2:g.113845C>G; NM_007294.4:c.424C>G; NP_009225.1:p.Pro142Ala39750915655152
NM_007294.4:c.4308T>CLebanonchr17:43082453BenignBenignBreast CancerNG_005905.2:g.135531T>C; NM_007294.4:c.4308T>C; NP_009225.1:p.Ser1436=1060915125703
NM_007294.4:c.4327C>TLebanonchr17:43082434PathogenicPathogenicBreast CancerNG_005905.2:g.135550C>T; NM_007294.4:c.4327C>T; NP_009225.1:p.Arg1443Ter4129345517675
NM_007294.4:c.4357+117G>ALebanonchr17:43082287BenignBenignBreast CancerNG_005905.2:g.135697G>A; NM_007294.4:c.4357+117G>A3737559125708
NM_007294.4:c.442-34C>T Lebanonchr17:43099914BenignBenignBreast CancerNG_005905.2:g.118070C>T; NM_007294.4:c.442-34C>T799923125864
NM_007294.4:c.4485-63C>G Lebanonchr17:43074584BenignBenignBreast CancerNG_005905.2:g.143400C>G; NM_007294.4:c.4485-63C>G273900734209374
NM_007294.4:c.4636G>ALebanonchr17:43074370BenignBenignBreast CancerNG_005905.2:g.143614G>A; NM_007294.4:c.4636G>A; NP_009225.1:p.Asp1546Asn2889769155245
NM_007294.4:c.4654T>CLebanonchr17:43074352Likely BenignLikely BenignBreast CancerNG_005905.2:g.143632T>C; NM_007294.4:c.4654T>C; NP_009225.1:p.Tyr1552His1265352633433716
NM_007294.4:c.466C>ALebanonchr17:43099856Breast CancerNG_005905.2:g.118128C>A; NM_007294.4:c.466C>A; NP_009225.1:p.Leu156Ile587778115233464
NM_007294.4:c.483_484TG[1]LebanonNC_000017.11:g.43099836_43099837CA[1]PathogenicPathogenicBreast CancerNG_005905.2:g.118145_118146TG[1]; NM_007294.4:c.483_484TG[1]; NP_009225.1:p.Val162fs8035770855304
NM_007294.4:c.4837A>GLebanonchr17:43071077BenignBenignBreast CancerNG_005905.2:g.146907A>G; NM_007294.4:c.4837A>G; NP_009225.1:p.Ser1613Gly179996641827
NM_007294.4:c.4956G>ALebanonchr17:43070958BenignBenignBreast CancerNG_005905.2:g.147026G>A; NM_007294.4:c.4956G>A; NP_009225.1:p.Met1652Ile179996741830
NM_007294.4:c.4985T>C LebanonNC_000017.11:g.43070929A>GBenign, Likely BenignUncertain SignificanceBreast CancerNG_005905.2:g.147055T>C; NM_007294.4:c.4985T>C ; NP_009225.1:p.Phe1662Ser2889769555339
NM_007294.4:c.5030_5033delLebanonchr17:43067652-43067655PathogenicPathogenic, Uncertain SignificanceBreast CancerNG_005905.2:g.150332_150335del; NM_007294.4:c.5030_5033del; NP_009225.1:p.Thr1677fs8035758037623
NM_007294.4:c.5153-66T>A Lebanonchr17:43063439Breast CancerNG_005905.2:g.154545T>A; NM_007294.4:c.5153-66T>A273901748125789
NM_007294.4:c.5187G>C Lebanonchr17:43063339Breast CancerNG_005905.2:g.154645G>C; NM_007294.4:c.5187G>C; NP_009225.1:p.Leu1729=1420995606865092
NM_007294.4:c.5194-26G>ALebanonchr17:43057161Breast CancerNG_005905.2:g.160823G>A; NM_007294.4:c.5194-26G>A761683937
NM_007294.4:c.5260G>CUnited Arab EmiratesNC_000017.11:g.43057069C>GBenign, Uncertain SignificanceUncertain SignificanceBreast-Ovarian Cancer, Familial, Susceptibility to, 1NG_005905.2:g.160915G>C; NM_007294.4:c.5260G>C; NP_009225.1:p.Glu1754Gln80357432462666
NM_007294.4:c.536A>GLebanonchr17:43099786BenignBenign, PathogenicBreast CancerNG_005905.2:g.118198A>G; NM_007294.4:c.536A>G; NP_009225.1:p.Tyr179Cys5618703337661
NM_007294.4:c.5406+68T>CLebanonchr17:43049053BenignBenignBreast CancerNG_005905.2:g.168931T>C; NM_007294.4:c.5406+68T>C8176307125842
NM_007294.4:c.5444G>ALebanonNC_000017.11:g.43047666C>TPathogenicPathogenicBreast CancerNG_005905.2:g.170318G>A; NM_007294.4:c.5444G>A; NP_009225.1:p.Trp1815Ter8035696255580
NM_007294.4:c.548-56del Lebanonchr17:43097346BenignBenignBreast CancerNG_005905.2:g.120639del; NM_007294.4:c.548-56del1567804371125894
NM_007294.4:c.81-91A>GLebanonchr17:43115870Breast CancerNG_005905.2:g.102114A>G; NM_007294.4:c.81-91A>G

Other Reports


Rouba et al. (2000) investigated the extent of allelic imbalance at the BRCA1 region in Arabic women with breast cancer. They conducted DNA analysis in 13 cases and analyzed microsatellite markers D17S1323, D17S1325 and D17S855 intragenic to BRCA1. Microsatellite analyses showed 12 of 13 (92%) cases with loss of heterozygosity or microsatellite instability or both. This observation led Rouba and colleagues to the conclusion that the proportion of aberrant findings of the BRCA1 locus in breast cancer appears to be higher in Arabic women than in other populations.

El-Harith et al. (2002) identified unclassified BRCA1 variant Phe486Leu, Asn550His, and five BRCA1 polymorphisms in a cohort of 29 Arab and 11 Asian women.


El-Harith et al. (2002) detected BRCA1 mutation Arg841Trp in an Arab patient from Egypt.


Bar-Sade et al., (1997) examined 639 unrelated healthy male and female Jews of Iraqi extraction and identified three individuals as c.185delAG mutation carriers; thus, a carrier rate of 0.47%. Haplotype analysis of the Iraqi mutation carriers showed that two of the Iraqis shared a haplotype in common with six Ashkenazi mutation carriers, and a third had a haplotype that differed by a single marker. This suggested to Bar-Sade et al. (1997) that the BRCA1 c.185delAG mutation may have arisen before the dispersion of the Jewish people in the Diaspora, at least at the time of Christ. Later, Bar-Saade et al. (1998) examined 43 unrelated women from Iraq for breast or ovarian cancer. They identified one patient with ovarian cancer as carrier for the 185delAG mutation in the BRCA1 gene.


Atoum and Al-Kayed (2004) screened exons 2, 11, and 20 of the BRCA1 gene in 135 Jordanian breast cancer females. Of the studied patients 50 had a family history of breast cancer, 28 had a family history of cancer other than breast cancer, and 57 had no family history of any cancer. Five germline mutations were detected among breast cancer females with a family history of breast cancers (one in exon 2 and 4 mutations in exon 11). Another germline mutation (within exon 11) was detected among breast cancer females with family history of cancer other than breast cancer, and no mutation was detected among breast cancer females with no family history of any cancer or among normal control females.


Amirrad et al. (2005) studied the expression of BRCA1 gene in Kuwait and compared it with the disease prognostic factors such as histological type and grade of breast cancer, C-erbB-2 expression, estrogen (ER) and progesterone (PR) receptor status, and age. BRCA1 gene expression was examined in 48 random samples of paraffin-embedded breast cancer tissues from Mubarak Al-Kabeer Hospital, while BRCA1 protein expression was investigated through Immunohistochemical method by employing antibodies on different epitopes on BRCA1 protein. Furthermore, BRCA1 mRNA expression was identified by using reverse transcription-polymerase chain reaction on 29 Kuwaitis (out of 48 patients). Amirrad et al. (2005) noticed that there was no obvious BRCA1 mRNA and protein expression in 79 and 83% of the breast cancer tissues, respectively. Additionally, negative expression of BRCA1 mRNA and/or protein was found to be associated with over expression of C-erbB-2, high histological grade and the lack of ER and PR receptor status in breast cancer tissues. This study shows that in Kuwait, the majority of breast cancers have negative BRCA1 gene expression and an opposite correlation among BRCA1 gene expression and the parameters that demonstrate poor prognosis in breast cancer.


Bar-Saade et al. (1998) examined 17 unrelated women from Morocco for breast or ovarian cancer. They identified one patient with ovarian cancer as carrier for the c.185delAG mutation in the BRCA1 gene. Bar-Saade et al. (1998) extended their analysis over DNA samples of 354 Jews of Moroccan origin, previously studied for Factor XI deficiency. They screened this group for the presence of the BRCA1 mutation c.185delAG in the germline and detected it in four individuals (1.1%).

Saudi Arabia

El-Harith et al. (2002) concluded that BRCA1 and BRCA2 mutations are likely to contribute to the pathogenesis of familial breast cancer in female patients from the Kingdom of Saudi Arabia.


Bar-Saade et al. (1998) examined three unrelated Syrian women tested for breast or ovarian cancer. They identified one patient with breast cancer as carrier for the 185delAG mutation in the BRCA1 gene. Haplotype analysis in the patient revealed a unique pattern not observed in other studied patients.


Mestiri et al. (2000) screened Tunisian women with familial or sporadic breast cancer for BRCA1 gene mutations using the Protein Truncation Test and DNA sequencing. A nonsense mutation was found in exon 11 of BRCA1 gene in a single case of familial breast cancer. DNA sequencing did not reveal any mutations in the other exons. The BRCA1 1294del40 mutation was found only in a patient with non familial breast cancer. The 185delAG mutation was absent in all cases of breast cancer. Mestiri and colleagues suggested that the germline mutation of BRCA1 is implicated in breast cancer in Tunisia and that the 185delAG mutation is absent in Arab Tunisian women.

Charef-Hamza et al. (2005) studied the role of BRCA1 in sporadic breast cancer among Tunisian women. Tumors from 21 patients undergoing surgery for breast cancer were examined and none of them had a family history of the disease. The subjects were screened with a panel of three polymorphic microsatellite markers (D17S1322, D17S1323, and EDH-17B) within the BRCA1 region to identify patients for loss of heterozygosity (LOH) BRCA1 status. Microsatellite DNA analysis identified 13 of the 21 informative tumors displaying allelic loss in at least one marker, and yielding a relatively high frequency (61.9%) of LOH at the BRCA1 loci. Charef-Hamza et al. (2005) indicated that the high frequency of LOH at BRCA1 might reflect tumor aggressiveness among Tunisian women. The highest frequency of LOH (58.8%) was observed at D17S1322, whereas the frequency of allelic loss was lower for the other two markers: 35% at D17S1323, and 20% at EDH-17B. The study indicated that at least two target regions in the vicinity of BRCA1 were involved in LOH suggesting deletions of all or part of the gene. There was no significant association between LOH in BRCA1 loci and tumor grade, therefore Charef-Hamza et al. (2005) concluded that deletions in the BRCA1 gene probably occurred early in sporadic mammary carcinogenesis among Tunisians.

United Arab Emirates

Denic and Al-Gazali (2002) examined the consequences of the long-term practice of consanguineous marriage on the prevalence of lethal cancer genes. Denic and Al-Gazali proposed that in a randomly mating population, the BRCA1/BRCA2 carrier rate decreases on average 0.0035% every 25 years. Whereas, in a highly consanguineous population, the carrier rate decreases on average 0.022% every 25 years, or six times faster than in a non-consanguineous population.

In a retrospective study of breast cancer patients in the UAE, Altinoz et al (2020) identified 7 Emirati patients with pathogenic variants in the BRCA1 gene. An additional four Emiratis were found to have variants of uncertain significance in the same gene.  


Bar-Saade et al. (1998) examined nine unrelated women from Yemen for breast or ovarian cancer. They identified two patients with ovarian cancers as carriers for the c.185delAG mutation in the BRCA1 gene. Haplotype analysis in one of the two patients revealed a unique pattern not available in other patients analyzed. Furthermore, Bar-Saade et al. (1998) extended their analysis over DNA samples of 200 Jews of Yemenite origin, previously studied for Factor XI deficiency, to screen for the presence of the BRCA1 mutation c.185delAG in the germline. The mutation was not found in any of the Yemenite patient group.

Lerer et al. (1998) described 8765delAG BRCA2 mutation in breast/ovarian cancer patients from three unrelated Jewish families of Yemenite origin.

[See also: BRCA2 gene > Arab, Yemen].

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