Four patients of two families with clinical characteristics resembling those in Marinesco-Sjögren syndrome are presented. All patients had infantile hypotonia as the presenting sign. In preschool age ataxia, cataract and mental retardation manifested. CT scan revealed cerebellar atrophy. Muscle biopsy showed myopathic changes with vacuolar degeneration and marked adipose tissue proliferation. Electron microscopy showed myelin bodies and autophagic vacuoles. The conclusion is that the peculiar myopathic and degenerative findings in the muscle biopsy are a consistent morphological feature in the clinical entity of the patients and the syndrome is distinctive from Marinesco-Sjögren syndrome.