Muscle function in a canine model of X-linked myotubular myopathy.

Introduction: We established a colony of dogs that harbor an X-linked MTM1 missense mutation.Muscle from affected male dogs exhibits reduction and altered localization of the MTM1 gene product, myotubularin, and provides a model analogous to X-linked myotubular myopathy (XLMTM).

Methods: We studied hindlimb muscle function in age-matched canine XLMTM genotypes between ages 9 and 18 weeks.

Eccentric contractions induce rapid isometric torque drop in dystrophin-deficient dogs.

We tested the hypothesis that eccentric contractions (ECCs) rapidly induce greater-than-normal isometric torque drop in dystrophin-deficient golden retriever muscular dystrophy (GRMD) muscles. ECCs were imposed by forcibly stretching activated muscles. The results indicate that isometric torque drop was greater in GRMD versus controls (P < 0.