Abstract for presentation at 11th International Congress of Human Genetics

It has been 10 years since the BRCA1 gene was first identified. During this decade, genetic testing for breast cancer susceptibility has been incorporated into the practice of oncology. In this process, the identification of families at the highest hereditary risk for cancer has served as a model to test strategies for prevention or early detection of breast malignancies. Here we report the first microarray-based resequencing analysis of the complete BRCA1 and BRCA2 genes. For this purpose, we used the oligonucleotide-microarray technology and designed a CustomSeq-Array for the coding region of both genes. Twenty-five unrelated patients and control persons were analysed. All exons of each sample were amplified by PCR using specific primers, pooled, labelled, fragmented, and hybridised to the BreastCancer-CustomSeq array. In addition all samples were confirmed by conventional sequencing procedure. All analysed BRCA mutations could be detected by the new diagnostic system. The BreastCancer-Array provides base calls at more than 99.5 accuracy which is comparable to capillary sequencing. Replicate experiments demonstrated a reproducibility of more than 99.95%. We conclude that array-based sequencing technology has the capability to efficiently and cost-effectively generate large-scale resequencing data of genes. The technology is in particular applicable to large genes with numerous different mutations, like BRCA, but is also utilized for highly heterogenous diseases. Furthermore CustomSeq arrays deliver a complete sequence within 48 hours which opens a revolutionary new era of sequence-based diagnostics.