General information:
The SALSA MLPA
Probemix P215 EXT is a
research use only (RUO) assay for the detection of deletions or duplications in the
EXT1 and
EXT2 genes, which are associated with Multiple Osteochondromas (MO). MO, also known as hereditary multiple exostoses, is inherited in an autosomal dominant manner. It is characterised by the development of multiple cartilage capped bony outgrowths, (mostly) on the metaphyses of the long bones, predominantly around the knee. Flat bones may also be affected, whereas facial bones usually remain unaffected. Osteochondromas are benign lesions with a risk of malignant transformation. Defects in the
EXT1 and
EXT2 genes on chromosomes 8 and 11, respectively, are the main cause of MO. These genes appear to function as tumour suppressor genes. The proteins encoded by the
EXT1 and
EXT2 genes are exostosin glycosyltransferases, involved in the chain elongation step of heparan sulfate biosynthesis in the Golgi apparatus.
EXT1 and
EXT2 have also been associated with other diseases. Langer-Giedion syndrome is caused by the deletion or mutation of at least two genes:
EXT1 and
TRPS1. The loss of
EXT1 causes the multiple exostoses seen in people with Langer-Giedion syndrome. Potocki-Shaffer syndrome is caused by a deletion at the short arm of chromosome 11 resulting in, amongst others, the deletion of the
EXT2 gene. The loss of
EXT2 is responsible for multiple exostoses in these patients.
More information is available at
https://www.ncbi.nlm.nih.gov/books/NBK1235/.
Probemix content:
The SALSA MLPA Probemix P215-B4 EXT contains 37 MLPA probes with amplification products between 130 and 441 nucleotides (nt). This includes 13 probes for the
EXT1 gene, one probe for each exon of the gene and two probes for exon 1 and exon 11, and 16 probes for the
EXT2 gene, one probe for each exon of the gene and one probe in intron 2. In addition, eight 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, 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.