A distal myopathy affecting young Rottweiler puppies was first described in 1998 (J Vet Intern Med 12:103-108) (Link to paper). All dogs in the original report were bred in Southern California. Clinical signs were identified between 3-8 weeks of age. The myopathy predominantly affected the distal limb muscles. Appendicular weakness was evidenced by postural abnormalities including hyperflexion of the hocks and carpi with a plantigrade and palmigrade stance (See video clip). Splaying of the digits was also observed. As the dogs grew in size, ambulation became very difficult and pressure sores developed.  Pathological changes within muscle biopsy specimens were consistent with a dystrophic type myopathy. Between 1998 and 2003 no additional cases were diagnosed at the Comparative Neuromuscular Laboratory. In 2003 the diagnosis was again confirmed in two young dogs. One dog was from Colorado and one from New York. History was not available on the dog from Colorado as it was obtained as a stray. The dog from New York was one of a litter of 9 puppies of which 5 were affected. Clinical signs were noticed between 3-7 weeks of age. Both sexes were affected. A muscle biopsy from one of the puppies confirmed the diagnosis.

            It appears that this condition is an inherited one and may be more widespread than initially thought. Since most of the inherited disorders of dogs and cats are recessive traits, elimination will likely require a molecular test to identify and select against carriers. The pattern of inheritance for this disorder has not yet been determined since such a small number of dogs have been confirmed. Exact diagnostic criteria must be established to determine which animals that look clinically similar actually have the same disease.  This is particularly important in young Rottweiler dogs since an inherited neuropathy, spinal muscular atrophy, and sex-linked muscular dystrophy can be found in dogs of this breed less than 6 months of age. A complete neurological evaluation of suspected puppies including determination of serum creatine kinase levels, electrophysiology, and muscle and peripheral nerve biopsies would be necessary for confirmation of the diagnosis.

            If this disorder is suspected, ask your veterinarian to contact Dr. Diane Shelton at the Comparative Neuromuscular Laboratory in San Diego (858 534-1537). Clinical information, pedigrees, and muscle biopsy information are currently being collected on this debilitating problem.