Intended purpose
The SALSA MLPA Probemix P017 MEN1 is an in vitro diagnostic (IVD)¹ or research use only (RUO) semi-quantitative assay² for the detection of deletions or duplications in the MEN1 gene in genomic DNA isolated from human peripheral whole blood specimens. P017 MEN1 is intended to confirm a potential cause for and clinical diagnosis of multiple endocrine neoplasia type 1 (MEN1) and for molecular genetic testing of at-risk family members.

Copy number variations (CNVs) detected with P017 MEN1 should be confirmed with a different technique. In particular, CNVs detected by only a single probe always require confirmation by another method. Most defects in the MEN1 gene are point mutations, none of which will be detected by MLPA. It is therefore recommended to use this assay 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
Multiple endocrine neoplasia (MEN) is an autosomal dominant cancer predisposition syndrome characterized by tumours found in two or more endocrine glands. MEN type 1 (MEN1) is primarily characterized by the occurrence of primary hyperparathyroidism (PHPT), which occurs in 95-100% of patients; pancreatic neuroendocrine tumours, which occur in 40-75% of patients; and pituitary adenoma, which is found in 30-50% of patients. Additionally, adrenal tumours, duodenal, thymic and lung neuroendocrine tumours, lipomas, facial angiofibroma, and collagenoma can be found. Most tumours are non-metastasizing, but many can cause striking and serious clinical effects due to increased secretion of hormones. It is estimated that in the general population 1 to 10 in 100.000 individuals develop MEN1 during their lifetime. Nine out of ten patients diagnosed with MEN1 have the familial form, and the penetrance is >95% by age 40 for confirmed pathogenic mutations. The mean age of death of MEN1 patients is between 50 and 55 years of age.

The single gene associated with MEN1 syndrome is MEN1. Heterozygous MEN1 pathogenic variants are found in ~90% of familial MEN1 syndrome patients and in ~65% of sporadic cases. Loss of heterozygosity (LOH) is frequently observed in MEN1 tumours suggesting that MEN1 acts as a tumour suppressor gene, as postulated by the Knudson 2-hit hypothesis. Besides point mutations, several deletions involving one or more complete exons in the MEN1 gene have been described (Carroll 2013, Concolino et al. 2016, Lemos and Thakker 2008, Romanet et al. 2019, Thakker 2014), including a pathogenic deletion of just the 5’-UTR (Kooblall et al. 2020).

Please note that this probemix is not suited to detect deletions or duplications in DNA extracted from fresh tumour tissue or from formalin-fixed paraffin embedded (FFPE) tumour materials. Probemix P244 (only version D1) can be used in a research setting to detect CNVs in the MEN1-region in DNA from tumour material.

Probemix content
The SALSA MLPA Probemix P017-D1 MEN1 contains 25 MLPA probes with amplification products between 142 and 373 nucleotides (nt). This includes 15 probes for the MEN1-region. 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.