title: Comparison of the phenotypes of patients harboring in-frame deletions starting at exon 45 in the Duchenne muscular dystrophy gene indicates potential for the development of exon skipping therapy.
abstract: Exon skipping therapy has recently received attention for its ability to convert the phenotype of lethal Duchenne muscular dystrophy (DMD) to a more benign form, Becker muscular dystrophy (BMD), by correcting the open reading frame. This therapy has mainly focused on a hot-spot (exons 45-55) mutation in the DMD gene. Exon skipping of an entire stretch of exons 45-55 is an approach applicable to 46.9% of DMD patients. However, the resulting phenotype is not yet fully understood. Here we examined the clinical profiles of 24 patients with BMD resulting from deletions starting at exon 45. The Δ45-55 group ranged in age from 2 to 87 years; no mortality was observed, and one patient was ambulatory at 79 years of age. The age at which patients became wheelchair-bound in the Δ45-48 group (18-88 years old) was approximately 50 years. Cardiomyopathy was well controlled by pharmaceuticals in both deletion groups. In contrast, the Δ45-47 and Δ45-49 groups exhibited more severe phenotypes than those with other mutations: the age at which patients in the Δ45-49 group became wheelchair-bound was around 30-40 years. Our study shows that clinical severity differs between each hot-spot deletion.
authors.affiliation: Third Department of Medicine, Shinshu University School of Medicine, Matsumoto, Japan.|Department of Neurology, National Hospital Organization, Matsumoto Medical Center, Matsumoto, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Nakamura
authors.affiliation: Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Shiba
authors.affiliation: Third Department of Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Daigo
authors.initials: D
authors.lastname: Miyazaki
authors.affiliation: School of Health Science, Shinshu University, Matsumoto, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Nishizawa
authors.affiliation: Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Inaba
authors.affiliation: Division of Rehabilitation, Nagano Children's Hospital, Azumino, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Fueki
authors.affiliation: Department of Medical Genetics, School of Human Development, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Rika
authors.initials: R
authors.lastname: Maruyama
authors.affiliation: Department of Medical Genetics, School of Human Development, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Echigoya
authors.affiliation: Department of Medical Genetics, School of Human Development, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Yokota
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D009202:Cardiomyopathies / Q000235:genetics / Q000473:pathology / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D016189:Dystrophin / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005260:Female; D015316:Genetic Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics* / Q000473:pathology / Q000628:therapy*; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000627:therapeutic use; D016366:Open Reading Frames; D017384:Sequence Deletion
chemical_list: C484258:DMD protein, human; D016189:Dystrophin; D016376:Oligonucleotides, Antisense