Intended purpose
The SALSA MLPA Probemix P159 GLA is an in vitro diagnostic (IVD)¹ or research use only (RUO) semi-quantitative assay² for the detection of deletions or duplications in the GLA gene in genomic DNA isolated from human peripheral whole blood specimens. P159 GLA is intended to confirm a potential cause for and clinical diagnosis of Fabry disease and for molecular genetic testing of at-risk family members.
Copy number variations (CNVs) detected with P159 GLA 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 GLA 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.

¹Please 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).
²To be used in combination with a SALSA MLPA Reagent Kit and Coffalyser.Net analysis software.

Clinical background
Fabry disease (OMIM: 301500) (Anderson-Fabry disease, Alpha-galactosidase A deficiency) is an X-linked disorder of glycosphingolipids that is caused by the deficiency of α-galactosidase A caused by defects in the galactosidase alpha (GLA) gene and usually has its onset in childhood or adolescence. Fabry disease is associated with the dysfunction of many cell types and includes a systemic vasculopathy (blood vessel disease). As a result, patients have a markedly increased risk of developing small-fiber peripheral neuropathy (disorders of the peripheral nervous system), stroke, myriad cardiac manifestations and chronic renal disease. Virtually all complications of Fabry disease are non-specific in nature and clinically indistinguishable from similar abnormalities that occur in the context of more common disorders in the general population.
Although this disease was originally thought to be very rare, studies have found a much higher incidence of mutations in the GLA gene, suggesting that this disorder is under-diagnosed (Schiffmann 2009).
More information is available at: https://www.ncbi.nlm.nih.gov/books/NBK1292/.

Probemix content
The SALSA MLPA Probemix P159-A5 GLA contains 25 MLPA probes with amplification products between 146 and 355 nucleotides (nt). This includes 8 probes for the GLA gene (one probe for each exon and an additional probe for exon 2), 3 flanking probes for genes located upstream of GLA (including HNRNPH2, reported to be part of a deletion also comprising GLA exons 1 and 2 (Schirinzi et al. 2008)) and 3 flanking probes for downstream genes. In addition, 11 reference probes are included that detect locations on the X-chromosome. Complete probe sequences and the identity of the genes detected by the reference probes are available online (www.mrcholland.com).
This probemix contains ten quality control fragments generating amplification products between 64 and 121 nt: four DNA Quantity fragments (Q-fragments), two DNA Denaturation fragments (D-fragments), one Benchmark fragment, and one chromosome X and two chromosome Y-specific fragments. 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.