A nonsense mutation effects mRNA splicing process of dystrophin gene

ABSTRACT

Background: Production of semi-functional dystrophin protein from the dystrophin gene encoded with a premature stop codon has been shown to modify the severe phenotype of Duchenne Muscular Dystrophy (DMD). The mutation of the dystrophin gene affects the process of complete mRNA and is important in gene therapy. Objective: To analyze the mutation of dystrophin gene in DMD cases. Subjects and methods: A patient with diagnosed with DMD when he was 2 years old, and at age 9, he was completely disabled and had to use a wheelchair. DNA and total RNA were extracted from fresh peripheral blood; cDNA was synthesized by transcript polymerase chain reaction (RT - PCR). PCR, nested PCR or sequence methods were used to determine the mutation of the dystrophin gene. Results: A nonsensical mutation (E638) due to a single nucleotide change in exon 17 of the dystrophin gene (GAA2047TAA) was identified. This mutation affects mRNA splicing process and induces complete exon 17 skipping. Conclusion: Patients, who had E638X mutation with exon 17 deletion in the dystrophin gene, had clinical symptoms of Becker Muscular Dystrophy (BMD). This discovery as a potential target for therapeutic strategies for DMD, to change the severe phenotype of DMD to a milder phenotype (BMD), in order to improve clinical conditions for the patients.