title: Muscular dystrophy in a family of Labrador Retrievers with no muscle dystrophin and a mild phenotype.
abstract: Animal models of dystrophin deficient muscular dystrophy, most notably canine X-linked muscular dystrophy, play an important role in developing new therapies for human Duchenne muscular dystrophy. Although the canine disease is a model of the human disease, the variable severity of clinical presentations in the canine may be problematic for pre-clinical trials, but also informative. Here we describe a family of Labrador Retrievers with three generations of male dogs having markedly increased serum creatine kinase activity, absence of membrane dystrophin, but with undetectable clinical signs of muscle weakness. Clinically normal young male Labrador Retriever puppies were evaluated prior to surgical neuter by screening laboratory blood work, including serum creatine kinase activity. Serum creatine kinase activities were markedly increased in the absence of clinical signs of muscle weakness. Evaluation of muscle biopsies confirmed a dystrophic phenotype with both degeneration and regeneration. Further evaluations by immunofluorescence and western blot analysis confirmed the absence of muscle dystrophin. Although dystrophin was not identified in the muscles, we did not find any detectable deletions or duplications in the dystrophin gene. Sequencing is now ongoing to search for point mutations. Our findings in this family of Labrador Retriever dogs lend support to the hypothesis that, in exceptional situations, muscle with no dystrophin may be functional. Unlocking the secrets that protect these dogs from a severe clinical myopathy is a great challenge which may have important implications for future treatment of human muscular dystrophies.
authors: The Division of Genetics and Genomics, Boston Children's Hospital, Department of Pediatrics and Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors: Natassia M
authors: NM
authors: Vieira
authors: Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA 92093.
authors: Ling T
authors: LT
authors: Guo
authors: The Division of Genetics and Genomics, Boston Children's Hospital, Department of Pediatrics and Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors: Elicia
authors: E
authors: Estrela
authors: The Division of Genetics and Genomics, Boston Children's Hospital, Department of Pediatrics and Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors: Louis M
authors: LM
authors: Kunkel
authors: Human Genome and Stem Cell Center, Biosciences Institute, University of Sao Paulo, Brazil.
authors: Mayana
authors: M
authors: Zatz
authors: Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA 92093. Electronic address: gshelton@ucsd.edu.
authors: G Diane
authors: GD
authors: Shelton
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004283:Dog Diseases / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D004285:Dogs; D016189:Dystrophin / Q000378:metabolism*; D005190:Family; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D009137:Muscular Dystrophy, Animal / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000209:etiology; D010375:Pedigree; D010641:Phenotype; D049411:Utrophin / Q000378:metabolism
chemical_list: D016189:Dystrophin; D049411:Utrophin
keywords: Animal model; Canine; Myopathy