General information
The SALSA MLPA Probemix P366 CHM-RP2-RPGR is a
research use only (RUO) assay for the detection of deletions or duplications in the
CHM,
RP2 and
RPGR genes, which are associated with X-linked retinitis pigmentosa and choroideremia.
Retinitis pigmentosa (RP) (prevalence 1/4000) 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. X-linked Retinitis Pigmentosa (xlRP) accounts for 5-15% of all RP syndromes. Mutations in the
RPGR (also called
RP3) and
RP2 genes are the most common causes of xlRP, responsible for 70-90% and 10-20% of the xlRP cases, respectively.
Choroideremia (CHM) is another X-linked recessive retinal degeneration disease which could be confused with X-linked retinitis pigmentosa. CHM is a rare inherited disorder that causes progressive loss of vision due to degeneration of the choroid and retina. This progressive X-linked retinopathy is caused by the deletion of the
CHM gene which encodes the Rab escort protein1 (REP1). REP1 is involved in the prenylation of Rabs. Under-prenylation of Rabs could affect vesicular trafficking, exocytosis and secretion in peripheral cells of CHM patients.
The
RPGR gene (19 exons) spans ~58 kb of genomic DNA and is located on Xp11.4, 38 Mb from the p-telomere. The
RP2 gene (5 exons) spans ~45 kb of genomic DNA and is located on Xp11.3, 47 Mb from the p-telomere. The
CHM gene (16 exons) spans ~186 kb of genomic DNA and is located on Xq21.2, 85 Mb from the p-telomere.
More information is available at
https://www.ncbi.nlm.nih.gov/books/NBK1417/ and
https://www.ncbi.nlm.nih.gov/books/NBK1337/.
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 P366-B1 CHM-RP2-RPGR contains 48 MLPA probes with amplification products between 130 and 483 nucleotides (nt). This includes 16 probes for the
RPGR gene, 5 probes for the
RP2 gene and 18 probes for the
CHM gene. In addition, nine 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 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.