General information
The SALSA MLPA Probemix P492 POLD1 - POLE is a research use only (RUO) assay for the detection of deletions or duplications in the POLD1 and POLE genes, which are associated with susceptibility to colorectal cancer. This probemix can also be used to specifically detect the wild-type sequence of the POLE c.1270C>G (p.Leu424Val) point mutation.

Susceptibility to colorectal cancer-10 (OMIM #612591) and susceptibility to colorectal cancer-12 (OMIM #615083) are autosomal dominant disorders conferred by mutations in the POLD1 and POLE genes, respectively. Patients show a predisposition to colorectal cancer, with onset at adult age but usually before the age of 40. Brain tumours and endometrial cancer have also been found in POLD1 and POLE mutation carriers. The human POLD1 and POLE genes encode subunits of the polymerase delta (POLδ) and polymerase epsilon (POLε) enzyme complexes, respectively. POLε is responsible for synthesis of the leading strand during DNA replication and POLδ is its equivalent lagging strand polymerase. Besides synthesis, these enzyme complexes also have proof-reading capacity via mismatch and base excision repair pathways. Mutations in POLD1 and POLE have been suggested to cause tumorigenesis due to decreased fidelity of polymerase proof-reading, leading to an increased mutation rate (Palles et al. 2013). The POLE c.1270C>G (p.Leu424Val) point mutation affects a highly conserved residue in the POLE proofreading domain and has been identified in different families with early-onset colorectal cancer (PMIDs 23447401, 24509466, 24501277, 25529843, 25124163 and 25370038).

The POLD1 gene (27 exons) spans ~34 kb of genomic DNA and is located on 19q13.33, about 56 Mb from the p-telomere. The POLE gene (49 exons) spans ~64 kb of genomic DNA and is located on 12q24.33, about 132 Mb from the p-telomere (close to the q-telomere).

This SALSA MLPA probemix is not CE/FDA registered for use in diagnostic procedures. Purchase of this product includes a limited license for research purposes.

Probemix content
The SALSA MLPA Probemix P492-A1 POLD1 - POLE contains 41 MLPA probes with amplification products between 136 and 454 nucleotides (nt). This includes 25 probes for the POLD1 gene; one probe for each exon except exons 4 and 7. Furthermore, this probemix contains six probes for the POLE gene, of which one probe detects the wildtype sequence at the POLE c.1270C>G mutation (p.Leu424Val). In addition, 10 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.