CANINE X-LINKED MUSCULAR-DYSTROPHY IN BELGIAN GROENENDAELER SHEPHERDS

A congenital myopathy is reported in a litter of Belgian Groenendaeler shepherds. The condition, affecting only male puppies, caused an abno rmal posture and gait and generalized muscle atrophy. Serum creatine k inase (CK) values were extremely high. Electromyographically, there we re complex repetitive discharges (pseudomyotonia). Histopathological e xamination revealed an increase in myofiber size variation and in inte rnal nuclei, and fibrosis. There was hypercontraction and hyalinizatio n of myofibers, myofiber necrosis, phagocytosis, and mineralization an d regeneration of myofibers. Clinical signs, serum biochemistry, and e lectrophysiological and pathological findings of this myopathy have mu ch in common with the canine X-linked muscular dystrophies and with Du chenne muscular dystrophy in man. Because of these similarities the au thors have chosen to call this myopathy ''Belgian Groenendaeler shephe rd muscular dystrophy'' (BGSMD).