title: First application of next-generation sequencing in Moroccan breast/ovarian cancer families and report of a novel frameshift mutation of theBRCA1gene.
abstract: At present, breast cancer is the most common type of cancer in females. The majority of cases are sporadic, but 5-10% are due to an inherited predisposition to develop breast and ovarian cancers, which are transmitted as an autosomal dominant form with incomplete penetrance. The beneficial effects of clinical genetic testing, including next generation sequencing (NGS) forBRCA1/2mutations, is major; in particular, it benefits the care of patients and the counseling of relatives that are at risk of breast cancer, in order to reduce breast cancer mortality.BRCAgenetic testing was performed in 15 patients with breast cancer and a family with positivity for the heterozygous c.6428C>A mutation of theBRCA2gene. Informed consent was obtained from all the subjects. Genomic DNAs were extracted and the NGS for genes was performed using the Ion Torrent Personal Genome Machine (PGM) with a 316 chip. The reads were aligned with the human reference HG19 genome to elucidate variants in theBRCA1andBRCA2genes. Mutations detected by the PGM platform were confirmed by target direct Sanger sequencing on a second patient DNA sample. In total, 4BRCAvariants were identified in 6 families by NGS. Of these, 3 mutations had been previously reported: c.2126insA ofBRCA1, and c.1310_1313delAAGA and c.7235insG ofBRCA2. The fourth variant, c.3453delT inBRCA1, has, to the best of our knowledge, never been previously reported. The present study is the first to apply NGS of theBRCA1andBRCA2genes to a Moroccan population, prompting additional investigation into local founder mutations and variant characteristics in the region. The variants with no clear clinical significance may present a diagnostic challenge when performing targeted resequencing. These results confirm that an NGS approach based on Ampliseq libraries and PGM sequencing is a highly efficient, speedy and high-throughput mutation detection method, which may be preferable in lower income countries.
authors.affiliation: Anoual Laboratory of Radio-Immuno Analysis, Casablanca 20360, Morocco; Laboratory of Pathophysiology and Molecular Genetics, Ben M'Sik Faculty of Science, Casablanca 7955, Morocco.
authors.forename: Farah
authors.initials: F
authors.lastname: Jouali
authors.affiliation: Department of Medical Genetics, National Institute of Health, Rabat 769, Morocco.
authors.forename: Fatima-Zahra
authors.initials: FZ
authors.lastname: Laarabi
authors.affiliation: Anoual Laboratory of Radio-Immuno Analysis, Casablanca 20360, Morocco.
authors.forename: Nabila
authors.initials: N
authors.lastname: Marchoudi
authors.affiliation: Department of Medical Genetics, National Institute of Health, Rabat 769, Morocco; Human Genome Center, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat 8007, Morocco.
authors.forename: Ilham
authors.initials: I
authors.lastname: Ratbi
authors.affiliation: Department of Medical Genetics, National Institute of Health, Rabat 769, Morocco; Human Genome Center, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat 8007, Morocco.
authors.forename: Siham Chafai
authors.initials: SC
authors.lastname: Elalaoui
authors.affiliation: Laboratory of Pathophysiology and Molecular Genetics, Ben M'Sik Faculty of Science, Casablanca 7955, Morocco.
authors.forename: Houria
authors.initials: H
authors.lastname: Rhaissi
authors.affiliation: Anoual Laboratory of Radio-Immuno Analysis, Casablanca 20360, Morocco.
authors.forename: Jamal
authors.initials: J
authors.lastname: Fekkak
authors.affiliation: Department of Medical Genetics, National Institute of Health, Rabat 769, Morocco; Human Genome Center, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat 8007, Morocco.
authors.forename: Abdelaziz
authors.initials: A
authors.lastname: Sefiani
keywords: BRCA1; BRCA2; Moroccan; breast cancer; families; mutation; next generation sequencing