title: Preimplantation genetic diagnosis using combined strategies on a breast cancer patient with a novel genomic deletion in BRCA2.
abstract: OBJECTIVE
  To perform Preimplantation Genetic Diagnosis (PGD) on a paternal Brca2 unknown mutation carrier with early-onset breast cancer, whose paternal grandmother and mother had breast cancer at 60s.
  
  
  METHODS
  Elucidating the linkage via single sperm haplotyping on patient's carrier brother, and identifying the genomic deletion via BLAST followed by PCR screening. PGD was subsequently conducted.
  
  
  RESULTS
  The mutant allele was found by using 4 microsatellite and 2 intragenic SNP markers. Recombination was detected in 8% of sperms. BLAST was utilized to locate putative hairpin structure(s), followed by PCR screening with seven sets of primers. A novel 2,596 bp deletion containing exon 15 ~ 16 was identified. Due to the severity of phenotype and the integrity of exon 11 encoding RAD51 binding domain, and the fact that the patient's mother also had breast cancer at her 60s, we speculate a possible coexistence of maternal breast cancer risk allele(s). Embryo biopsy was performed on day 3. Unaffected morula and blastocyst were replaced on day 5, resulting in a singleton livebirth. A breast lump appeared in the patient after delivery without the presence of malignant cells.
  
  
  CONCLUSIONS
  Concerning the assisted reproductive option for breast cancer patients, the possibility of coexistence of multiple familial risk alleles and the significance of each mutation to the phenotype should be evaluated. To eliminate misdiagnosis resulting from recombination and/or allelic drop-out, both direct mutation detection and linkage analysis approaches may be necessary. BLAST is a very useful and cost-effective tool for identifying large genomic deletion.
authors.affiliation: Department of Obstetrics and Gynaecology, Queen Mary Hospital, University of Hong Kong, Rm 0528, Block K, 102 Pokfulam Road, Hong Kong, China, qxwang@hku.hk.
authors.forename: Qingxue
authors.initials: Q
authors.lastname: Wang
authors.forename: Judy F C
authors.initials: JF
authors.lastname: Chow
authors.forename: William S B
authors.initials: WS
authors.lastname: Yeung
authors.forename: Estella Y L
authors.initials: EY
authors.lastname: Lau
authors.forename: Vivian C Y
authors.initials: VC
authors.lastname: Lee
authors.forename: Ernest H Y
authors.initials: EH
authors.lastname: Ng
authors.forename: Pak-Chung
authors.initials: PC
authors.lastname: Ho
mesh_terms: D000328:Adult; D024682:BRCA2 Protein / Q000235:genetics; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D005260:Female; D006239:Haplotypes; D006801:Humans; D050498:Live Birth; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011247:Pregnancy; D019836:Preimplantation Diagnosis; D011995:Recombination, Genetic; D017384:Sequence Deletion / Q000235:genetics*; D059010:Single-Cell Analysis; D013094:Spermatozoa / Q000473:pathology
chemical_list: D024682:BRCA2 Protein; C551750:BRCA2 protein, human