DNA test
The muscle-specific isoform of the dystrophin gene is composed of 79 exons, and DNA testing (blood test) and analysis can usually identify the specific type of mutation of the exon or exons that are affected. DNA testing confirms the diagnosis in most cases. Muscle biopsy
If DNA testing fails to find the mutation, a muscle biopsy test may be performed. A small sample of muscle tissue is extracted using a biopsy needle. The key tests performed on the biopsy sample for DMD are immunohistochemistry, immunocytochemistry, and immunoblotting for dystrophin, and should be interpreted by an experienced neuromuscular pathologist. These tests provide information on the presence or absence of the protein. Absence of the protein is a positive test for DMD. Where dystrophin is present, the tests indicate the amount and molecular size of dystrophin, helping to distinguish DMD from milder dystrophinopathy phenotypes. Over the past several years, DNA tests have been developed that detect more of the many mutations that cause the condition, and muscle biopsy is not required as often to confirm the presence of DMD. Prenatal tests
A prenatal test can be considered when the mother is a known or suspected carrier.Prenatal tests can tell whether the unborn child has one of the most common mutations.
This functional, yet truncated, form of dystrophin gave rise to the notion that shorter dystrophin can still be therapeutically beneficial. Concurrently, Kole et al. had modified splicing by targeting pre-mRNA with antisense oligonucleotides (AONs). Kole demonstrated success using splice-targeted AONs to correct missplicing in cells removed from beta-thalassemia patients Wiltons group tested exon skipping for muscular dystrophy. Gene therapy
Researchers are working on a gene editing method to correct a mutation that leads to Duchenne muscular dystrophy (DMD). Researchers used a technique called CRISPR/Cas9-mediated genome editing, which can precisely remove a mutation in the dystrophin gene in DNA, allowing the bodys DNA repair mechanisms to replace it with a normal copy of the gene. The benefit of this over other gene therapy techniques is that it can permanently correct the "defect" in a gene rather than just transiently adding a "functional" one.Genome editing through the CRISPR/Cas9 system is not currently feasible in humans. However, it may be possible, through advancements in technology, to use this technique to develop therapies for DMD in the future. In 2007, researchers did the worlds first clinical (viral-mediated) gene therapy trial for Duchenne MD.Biostrophin is a delivery vector for gene therapy in the treatment of Duchenne muscular dystrophy and Becker muscular dystrophy. References
Further reading
Birnkrant DJ, Bushby K, Bann CM, Apkon SD, Blackwell A, Brumbaugh D,  et al. (March 2018). "Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and neuromuscular, rehabilitation, endocrine, and gastrointestinal and nutritional management". Lancet Neurol. 17 (3): 251–267. doi:10.1016/S1474-4422(18)30024-3. PMC 5869704. PMID 29395989.