General information
The SALSA MLPA Probemix P360 Y-Chromosome is a research use only (RUO) assay for the detection of deletions or duplications in the azoospermia factors (AZF) regions on the Y chromosome, which are associated with spermatogenetic failure in infertile men.

Microdeletions of the Y chromosome are the second most frequent genetic cause of spermatogenetic failure in infertile men after Klinefelter syndrome. These microdeletions are caused by intrachromosomal recombination events between large homologous repetitive sequence blocks (Foresta et al. 2001) and are clustered in three specific regions on the long arm of the Y chromosome, designated as azoospermia factors (AZF) loci: AZFa (~13.1-15.2 Mb from the p-telomere), AZFb (~18.5-22.8 Mb) and AZFc (~23.3-25.5 Mb) (Vogt et al. 1996). The most frequent type is the AZFc region deletion (~80%) followed by AZFa (0.5-4%), AZFb (1-5%) and AZFbc (1-3%) deletions (Krausz et al, 2014). Deletions which are detected as AZFabc are most likely related to abnormal karyotype such as 46,XX male or iso (Y) (Lange et al. 2009).

Inconsistent findings on the clinical effects of AZF-linked duplications (Giachini et al. 2008 and Lin et al. 2007), demonstrate the necessity of further research, for which at present, MLPA offers the most suitable technology.

This probemix contains probes for regions AZFa, AZFb and AZFc. The mix includes three probes which detect a sequence that is present three times across these regions and seven probes which detect a sequence that is present twice. See Table 1 (in the Product Description) for an overview of the probes and the number of sequences detected. Table 3 (in the Product Description) details the probes mapped to the AZF regions.

The best characterised AZFc deletion spans the whole AZFc region (about 3.5 Mb), however, partial AZFc deletions are also known. In a recent large study (Rozen et al. 2012) the frequency of four recurrent partial AZFc deletions was studied in five populations. It was found that partial (interstitial) AZFc deletions are more common among individuals with severe spermatogenic failure than in controls. However, it is important to note that certain partial AZFc deletions, such as the 1.6 Mb gr/gr deletion, are also present in high frequency in fertile men (Machev et al. 2004 and Hucklenbroich et al. 2005).

Finally, this probemix contains one probe detecting the SRY gene on the p arm of the Y chromosome and 12 reference probes that detect several different autosomal chromosomal locations.

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 P360-B2 Y-Chromosome contains 55 MLPA probes with amplification products between 130 and 507 nucleotides (nt). This includes 43 probes spread over the relevant regions of the Y chromosome. In addition, 12 reference probes are included that detect 12 different 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.