The Analysis Of Pathogenic Gene Mutation In Hereditary Multiple Osteochondroma

Hereditary multiple osteochondroma,(alias hereditary multiple exostoses), is a common autosomal dominant inheritabledisease of skeletal system. The character of this disease is the bone cartilage at the surface of the cap was formed from the bone, which accompany many complications such as joint pain, limited motion, long bone morphology anomalies, tumors compressing adjacent vascular and nerve. Moreover it have the chance to become chondrosarcoma (canceration rate about0.5%-5%). Some studies indicated that HME have strong genetic heterogeneity. EXT gene families are composed with the EXT1, EXT2, EXT3, EXTL1, EXTL2and EXTL3. Due to the mutations of EXT gene, EXT gene has the ability to cause Ihh、Wnt and BMP signaling pathways’s abnormal, which can affect the proliferation of cartilage cell, sequentially, it can lead to the formation of osteochondroma eventually. Various studies have indicated that the pathogenic gene of HME, associated with the EXT1and EXT2, and they have been cloned. Therefore, in except the above mutation of the EXT1and EXT2, whether there is a new genes mutation in EXT still needs further post-research.Objective:Through PCR to defect coding sequence of the pathogenic gene EXTl and EXT2for the HME family, we try to find out the pathogenic mutations of this HME family. To explore and analyse the related gene mutations of hereditary multiple osteochondroma, and preliminary grasp the screening methods of the disease-causing gene mutations, such as PCR and sequencing. And to further analyse the function changes of gene mutation.Methods:One case of the HME pedigree from LouDi Hunan has collected. The pedigree have4generations,21people and7patients.3patients’s blood samples were collected. Through extracting DNA and standardizing the DNA concentration,20primers was designed by primer3software online, according to the design parameters of primer, EXTl and EXT2gene coding area and the flanking sequence of exon were amplified by PCR, and the result was confirmed by the polyacrylamide gel electrophoresis. And finally the products of PCR was directed by sequencing. And analysis of the results was performed by the DNA star software, to compare the variations in db SNP database, which could eliminate the SNP.Result:The EXT1and EXT2gene’s enzymatic mutation detection has accomplished for the patient (Ⅱ:3,Ⅲ:3,Ⅳ:2)within genealogy, By exon sequencing, no variation was found in the EXT1’s hot spots; three SNPS (rs10769018、rs4755228、rs11037909) were found in the EXT2’s hot spots. But no other mutation had been defected in code areas and exons-introns border areas.Conclusion:The genetic mutation for this family does not exist in the areas of the EXT1, EXT2’s hot spots. The results can provide possibility that a new gene mutation is found in further study, which is good for elucidating the detailed pathogenesis of EXT.