Muscular dystrophies definition

Myopathy is the term used broadly for affections of the skeletal musculature, in which the muscular symptoms in no way arise from disordered function of the central or peripheral nervous system. Within this definition are included, therefore, such widely differing conditions as the polymyositis syndrome, endocrine myopathies associated with thyroid gland disorders, and the muscular dystrophies. 

Hydroxyproline excretion, however, is decreased in Duchenne dystrophy at all stages (K4) in other muscle diseases the changes were less definite. As this amino acid occurs in collagen and elastin, its diminished excretion may be related to the formation of extra connective tissue in muscular dystrophy. 

---