A normal life without muscle dystrophin

• GRMD dog with no dystrophin and normal lifespan
• Mild phenotype in a GRMD dog and one of his offspring
• Mild phenotype in GRMD dogs is not related to utrophin upregulation.

Here we summarize the clinical history of Ringo, a golden retriever muscular dystrophy (GRMD) dog, who had a mild phenotype despite the absence of muscle dystrophin. Ringo died of cardiac arrest at age 11 and therefore displayed a normal lifespan. One of his descendants, Suflair, born April 2006, also displays a mild course. Dystrophin analysis confirmed total absence of muscle dystrophin in both dogs. Muscle utrophin expression did not differ from severely affected GRMD dogs. Finding what protects these special dogs from the dystrophic degeneration process is now a great challenge that may open new avenues for treatment. But most importantly, the demonstration that it is possible to have a functional muscle, in a medium-large animal even in the absence of dystrophin, brings new hope for Duchenne patients.