General information: The SALSA MLPA Probemix P235 Retinitis is a research use only (RUO) assay for the detection of deletions or duplications in the RHO, IMPDH1, RP1, and PRPF31 genes, which are associated with Retinitis Pigmentosa (RP).

RP is a hereditary degenerative disease of the photoreceptor neurons of the retina. RP is characterized by progressive degeneration of the peripheral retina (leading to night blindness), loss of the peripheral visual field, and an abnormal electroretinogram. The genes most frequently involved in RP are RHO, IMPDH1, RP1, and PRPF31. Rhodopsin (RHO) is a highly-specialized G protein-coupled receptor that detects photons in the rod photoreceptors of vertebrates. Mutations in IMPDH1, a widely expressed rate-limiting enzyme of the de novo pathway of guanine nucleotide biosynthesis, have been shown to cause autosomal dominant RP. The gene for human oxygen regulated photoreceptor protein (RP1) encodes a protein that is localized in the connecting cilia of both rod and cone receptors. The RP1 protein is required for the morphogenesis of the outer segments of photoreceptor cells. Mutations in RP1 cause at least 7% of autosomal dominant RP. Lastly, PRPF31 encodes a 61 kDa protein which is essential for splicing in all cell types. The pathologic effect of mutations in this gene can be seen in rod photoreceptors. Furthermore, this probemix contains also a probe for RPE65 gene which is also linked to RP.

More information is available at https://www.ncbi.nlm.nih.gov/books/NBK1417/.

Probemix content: The SALSA MLPA Probemix P235-B3 Retinitis contains 44 MLPA probes with amplification products between 130 and 463 nucleotides (nt). This includes five probes for the RHO gene, one probe for each exon, nine probes for the IMPDH1 gene, targeting nine out of 17 exons, five exons for the RP1 gene, one probe for each exon and an extra probe for exon 1, 15 probes for the PRPF31 gene, one probe for each exon and two probes for exon 1, and one probe targeting exon 7 of the RPE65 gene. 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.mlpa.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.mlpa.com.