The cases of three brothers with proximal weakness and muscles atrophies beginning in childhood are reported. Muscles biopsies and electromyographic studies have shown neurogenic pattern of atrophy and a dystrophy-like picture. It is concluded that this histological and eletromyographic picture can occur in pure partial denervation of long standing. The histopathologic study of the spinal cord of one patient revealed degenerative changes and loss of anterior horn ganglion cells. This is the fourth case of Wohlfar -Kugelberg-Welander disease with postmortem examination.