Intended purpose
The SALSA MLPA Probemix P002 BRCA1 is an in vitro diagnostic (IVD)
1 or research use only (RUO) semi-quantitative assay
2 for the detection of deletions or duplications in the human
BRCA1 gene in genomic DNA isolated from human peripheral whole blood specimens. P002 BRCA1 is intended to confirm a potential cause for and clinical diagnosis of hereditary breast and ovarian cancer (HBOC) syndrome and for molecular genetic testing of at-risk family members.
Copy number variations (CNVs) detected with the P002 BRCA1 probemix should be confirmed with the SALSA MLPA P087 BRCA1 Confirmation probemix or a different technique. In particular, CNVs detected by only a single probe always require confirmation by another method. Most defects in the
BRCA1 gene are point mutations, none of which will be detected by MLPA. It is therefore recommended to use this SALSA MLPA probemix in combination with sequence analysis.
Assay results are intended to be used in conjunction with other clinical and diagnostic findings, consistent with professional standards of practice, including confirmation by alternative methods, clinical genetic evaluation, and counselling, as appropriate. The results of this test should be interpreted by a clinical molecular geneticist or equivalent.
This device is not intended to be used for standalone diagnostic purposes, pre-implantation or prenatal testing, population screening, or for the detection of, or screening for, acquired or somatic genetic aberrations, e.g from DNA extracted from formalin-fixed paraffin embedded (FFPE) or fresh tumour materials.
1 Please note that this probemix is for in vitro diagnostic (IVD) use in the countries specified at the end of this product description. In all other countries, the product is for research use only (RUO).
2 To be used in combination with a SALSA MLPA Reagent Kit and Coffalyser.Net analysis software.
Clinical background
Breast and ovarian carcinomas are among the most common malignancies in developed countries. The majority of cases are considered sporadic, but in a substantial portion, a clear history of cases within a family is present. The BRCA1 and BRCA2 proteins are associated with the activation of double-strand break repair and homologous recombination and are important in maintaining genomic stability. Germline defects in the
BRCA1 gene are the most frequent cause of a hereditary predisposition to breast cancer. Features characteristic of hereditary, versus sporadic, breast cancer are: younger age at diagnosis, frequent bilateral disease, and more frequent occurrence of diseases such as prostate and breast cancer among male relatives. Mutations in the
BRCA1 and
BRCA2 genes account for about 20-25% of hereditary breast cancers (Easton 1999) and about 5-10% of all breast cancers (Campeau et al. 2008). In addition, mutations in the
BRCA1 and
BRCA2 genes account for around 15% of ovarian cancers (Pal et al. 2005). Women with a germline
BRCA1 mutation
have a 55-72% risk of developing breast cancer by age 70, while the risk of women in the general population is 12%. The lifetime risk of developing ovarian cancer in women with a germline
BRCA1 mutation is 39-44%, compared to 1-2% in the general population.
The great majority of germline defects in the
BRCA1 gene are point mutations that can be detected by sequence analysis. Deletions and duplications of complete exons in the
BRCA1 gene are the second most common cause of defects in the
BRCA1 gene. These copy number changes are usually missed by amplicon-based sequencing analysis (Sanger sequencing or Next Generation Sequencing), but can be detected by MLPA and hence MLPA complements sequence analysis of the
BRCA1 gene. CNVs in
BRCA1 account for 11-13% of all
BRCA1 pathogenic mutations, dependent on the population. Some populations have a higher prevalence of CNVs in HBOC patients. For example in Italian HBOC families the prevalence is 23% (Montagna et al. 2003), in the Netherlands 27-36% (Hogervorst et al. 2003; Petrij-Bosch et al. 1997), while in a Danish cohort of HBOC patients the prevalence was 3.8% (Thomassen et al. 2006).
More information is available at
http://www.ncbi.nlm.nih.gov/books/NBK1247/.
Probemix content
The SALSA MLPA Probemix P002-D1 BRCA1 contains 48 MLPA probes with amplification products between 130 and 469 nucleotides (nt). This includes 38 probes for the
BRCA1 gene region. At least one MLPA probe is present for each exon in the major
BRCA1 transcript variant 1. Eight probes are present for exon 11 (3426 nt long). Three probes are present for exon 13, which is frequently deleted or duplicated (Hogervorst et al. 2003). Three probes are present for exon 24 and two probes for exon 16. One probe is included for exon 1b, an alternative first exon that is not present in
BRCA1 transcript variant 1, and two probes detect sequences located 4.7 kb and 0.8 kb upstream of the
BRCA1 gene to determine the extent of the deletion or duplication. In addition, ten reference probes are included that detect autosomal chromosomal locations. Complete probe sequences and the identity of the genes detected by the reference probes are available online (
www.mrcholland.com).
This probemix contains nine quality control fragments generating amplification products between 64 and 105 nt: four DNA Quantity fragments (Q-fragments), two DNA Denaturation fragments (D-fragments), one Benchmark fragment, and one chromosome X and one chromosome Y-specific fragment. More information on how to interpret observations on these control fragments can be found in the MLPA General Protocol and online at
www.mrcholland.com.
SALSA Artificial Duplication DNA SD024
In case no positive DNA sample is available in your laboratory, an artificial duplication DNA sample for this probemix (catalogue number SD024) can be ordered from MRC Holland. This SD024 Artificial Duplication DNA will show a duplication of two or three probes when using the following probemixes: P002 and P087 BRCA1; P045, P090 and P077 BRCA2. The SD024 Artificial Duplication DNA is a mixture of human female genomic DNA and a titrated amount of plasmid containing selected probe target sequences. For further details, please consult the SD024 Artificial Duplication DNA product description, available online:
www.mrcholland.com.
This product is for research use only (RUO).
Sample DNA
Sample DNA developed for this product: