DUCHENNE MUSCULAR DYSTROPHY - GENETICS: P.214Genetic profile of Chilean patients with Duchenne muscle dystrophy

Abstract

Duchenne muscle dystrophy (DMD), is a progressive muscular disease, inherited as a X link. Is caused by the mutations of the dystrophin gene. Deletions of one or more exons account for approximately 50-65%, duplications 5-10% and point mutations 20-25%. Analyze the genetic profile of patients with DMD through regular checkups at the pediatric neurology department of the San Borja Arriarán Hospital. Retrospective descriptive study. Analysis of clinical records of 41 patients in evaluation by DMD, excluding patients diagnosed prior to the year 2010, with only biopsy and/ or PCR (polymerase chain reaction) without alterations. 41 patients with clinical manifestations and/or muscle biopsy with markedly reduced or no detectable dystrophin immunostaining, were studied by PCR, MLPA (multiplex ligation probe amplification) and/or Sanger sequencing techniques. 27/41 (66%) of patients had large deletions, 20/27 had compromised exons 44-55, and 3/26 had compromised exons 3-7. The most frequent deletion was exon 50, followed by exon 49. 3/41 (7,3%) presented duplications, which all affected exon 2. 10/41(24,4%) of patients had a negative MLPA, but a compatible muscle biopsy. In 1/41, sequencing was performed, showing nonsense mutation, in exon 41. Our study of the genetic profile of chileans patients is similar to previously reported, deletions are the most frequent alterations. It should be noted that biopsy continues to be an important tool for confirming diagnostics, due to our countries limited access to sequencing techniques. Because of this, we can extrapolate and conclude that the large percentage of patients with compatible muscle biopsy and negative MLPA, could correspond to point mutations, which would then coincide with the published. Therefore, it is important to make genetic diagnosis advances thus giving us the possibility of integrating new therapies and the ability to offer genetic counseling.