Application Guide - QIAxcel Advanced

44 QIAxcel Advanced Application Guide 10/2016 Rapid Analysis of Deletions/Duplications with MLPA® Using the QIAxcel® Advanced System Fischer S.B.1 , Herms S.1 , Cichon S.1 , Aretz, S.2 , Hoffmann P.1,2 , and Kozulić M.3 1 Human Genomics Research Group, Department of Biomedicine, University of Basel, Basel, Switzerland 2 Instiute of Human Genetics, University of Bonn, Bonn, Germany 3 QIAGEN Instruments AG, Garstligweg 8, 8634 Hombrechtikon, Switzerland Introduction Adenomatous polyposis syndromes are characterized by polyps in the colorectum. When untreated, these pre-malignant polyps almost always become malignant and lead to colorectal cancer (1). Age of onset for colon cancer is around 39 years, though individuals may develop multiple benign colon polyps in their teenage years. Three monogenic inherited forms have been molecularly diagnosed and distinguished: • Familial adenomatous polyposis (FAP) • MUTYH-associated polyposis (MAP) • Proofreading-associated polyposis (PPAP) FAP is the autosomal dominant form caused by mutations or deletions/duplications in the adenomatouspolyposis coli (APC) gene located on chromosome 5q22. Hundreds of different variations in the APC gene have been described. The detection rate for a pathogenic APC mutation in index patients with classical FAP is 80–90%. Attenuated FAP (AFAP) is a second form of FAP with a milder course of disease. The detection rate for APC and MUTYH mutations in AFAP for index patients is around 20–30%. For clinical diagnosis of a classical or attenuated FAP, persons must have at least 10 synchronous adenomatous polyps (2,3). Molecular genetic analysis frequently uses either capillary (Sanger) or next-generation sequencing of all exons of the genes involved in the development of FAP, AFAP and PPAP. In classical FAP, genomic rearrangements are caused by large deletions in <10%–15% and rarely by large duplications (3,4). To detect these events in the APC and MUTYH genes, a Multiplex Ligation-dependent Probe Amplification (MLPA® ) can be conducted with subsequent fragment analysis on a capillary (Sanger) sequencer, which is a costly and time-consuming method.

Pages Overview