Gene Diagnosis And Prenatal Diagnosis For Duchenne And Beckermuscular Dystrophy

Objective1、To establish the Multiple ligation probe amplification (MLPA) assay to improve the detection rate of mutations in the DMD gene diagnosis and prenatal diagnosis.2、To investigate the predictive value of mPCR and MLPA in DMD gene diagnosis.,3、Use of MLPA to detect the carrier of mutation in DMD gene. To establish a feasible and effective prenatal diagnosis assay in DMD and BMD. Offering the family a high quality and quick genetic counseling to reduce the incidence of major birth defects.4、To anaysis the mutation spectrum of Dystrophin gene within populations in Yunnan province.Methods1、Multiplex polymerase chain reaction(mPCR) was applied for deletion analysis of18exons of DMD gene with higher deletion frequency in126cages of suspected DMD/BMD who visited the Genetic Diagnosis Center of the First People’s Hospital of Yunnan Province.2、SRY gene was detected in15pregnantal women with a history of DMD/BMD by PCR. The analysis of deletion for the18frequency deletion exon and the linkage of5short tandem repeat in DMD gene was carried out for prenatal diagnosis.3、Dystrophin gene was detected by MLPA in34patients with DMD/BMD and it were verified by PCR for a single exon deletion.4、Carrier was detected by MLPA in8mothers of patient with deletion mutation. Use the MLPA technique to analysis the79exons in2pregnantal women and the linkage of short tandem repeat in DMD gene was carried out for prenatal diagnosis. 5、Distribution of dystrophin gene exons deletion was summarized consequently.Results1、80cases were detected to have deletion of one or more Dystrophin exons in136patients, and no deletions could be detected in the remaining56patients. Eliminating the10female cases, Multiplex PCR can detect63.5%of DMD gene deletions in the DMD/BMD patients.2、The test of SRY gene revealed11male and4female in the15fetuses. The result showed that2in11male fetuses were DMD/BMD casese;1in4female fetuses was gene mutation carrier, and1fetuses do not get information by STR analysis.3、16cases were detected to have deletion of one or more Dystrophin exons in34patients detected by MLPA, and no deletions or reduplication could be detected in the remaining19patients. Eliminating the4female cases and2SMA patients, MLPA can detect57.1%of DMD gene mutation in the DMD/BMD patients. MLPA detected2patients with deletion of exton21and70which mPCR cann’t detected.4、3of the8mothers of patient with deletion mutation were identified as carrier detected by MLPA.2pregnatal women with a history of DMD/BMD detected by MLPA showed that1female fetuses was identified as carrier and1female fetus was normal fetus. The result of MLPA was consistent with STR.5、88.7%exon deletion occurred in the central region of DMD gene within populations in Yunnan province.Conclusions1-We have established the Multiple ligation probe amplification (MLPA) assay to detect the mutations in the DMD and BMD for gene diagnosis and prenatal diagnosis.2、MLPA can detect the deletion and duplication mutation of all the79exons of Dystrophin gene, improving the efficiency, sensitivity and stability of genetic diagnosis. Detection of a single exon deletion by PCR can improve the accuracy of the results. MLPA can detect more about7%of DMD gene mutation than mPCR.3、MLPA can quantify the copy number of dystrophin gene accurately, being adequate for detecting carrier and providing reliable evidence for genetic counseling. MLPA combinded with STR is the ideal method for prenatal diagnosis in DMD/BMD.4、Exon deletion occurred mostly (88.7%) in the central region of DMD gene within populations in Yunnan province.