General information
The SALSA MLPA Probemix P292 PCDH15 is a
research use only (RUO) assay for the detection of deletions or duplications in the
PCDH15 gene, which is associated with Usher syndrome.
Usher syndrome is a heterogeneous autosomal recessive disorder characterised by hearing loss and retinitis pigmentosa. Three clinical types (USH1, -2, and -3) are defined with respect to the degree and progression of hearing loss and the presence or absence of vestibular dysfunction. Usher syndrome type I (USH1) is the most disabling form, while USH2 is the most common of the three types of Usher syndrome. The following six genes have been identified for USH1:
MYO7A (Myosin VIIA, USH1B),
USH1C (Usher syndrome 1C),
CDH23 (Cadherin related 23, USH1D),
PCDH15 (Protocadherin related 15, USH1F),
USH1G (Usher syndrome 1G) and
CIB2 (Calcium and integrin binding family member 2, USH1J). Mutations in the
PCDH15 gene are associated with Usher syndrome type 1F (USH1F). The gene has been shown to be particularly prone to large rearrangements (Roux et al. 2011). The
PCDH15 gene (33 exons) spans ~1 Mb of genomic DNA and is located on 10q21.1, ~55 Mb from the p-telomere. The gene is a member of the cadherin superfamily and encodes for an integral membrane protein that mediates calcium-dependent cell-cell adhesion.
More information is available at
https://www.ncbi.nlm.nih.gov/books/NBK1265/.
Probemix content
The SALSA MLPA Probemix P292-B2 PCDH15 contains 42 MLPA probes with amplification products between 130 and 463 nucleotides (nt). This includes 33 probes for the
PCDH15 gene: one probe for each exon with the exception of exon 31 and 32, and a second probe for both exon 1 and 2. In addition, nine 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 (see table below). 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.