Genetic, elettromyographic, enzymological and histological aspects of two cases of proximal pseudomyopathic spinal amyotrophy are described. The former is related to a typical Wohlfart-Kugelberg-Welander syndrom with characteristics of recessive autosomal heredity. It is related to a fifteen-years old patient who, since he was ten has been affected by progressively increasing muscular hypotrophy. It was localized mostly on the scapular girdle and less on the pelvic girdle, with tendency to extend to the distal muscles of the limbs, without fasciculations or sensory symptoms. Serum enzyme levels were normal. Both muscular biopsy and electromyographic tests yield reports testifying a spinal amyotrophy. The later is related to a spinal pelvic girdle amyotrophy arisen in a thirty-three-year old subject who since twenty-nine has started to present weakness and hypotrophy of pelvic girdle muscles and of the roots of the thighs particulary involving the adducent muscles. There were neither amyotrophies in other districts nor fasciculations. Serum enzyme levels were normal. Muscular biopsy clearly proved a neurogenic amyotrophy. E.M.G. showed signs of myogenic and neurogenic sufference. Problems concerning the nosographic delimitation of different spinal muscular atrophies are discussed on the ground of literature, too.