[Occipital horn syndrome (Ehlers-Danlos syndrome type IX) with severe psychomotor retardation and muscle atrophy--a first Japanese case].

Occipital horn syndrome (OHS; Ehlers-Danlos syndrome type IX) belongs to the category of the copper metabolism disorders and is at present being investigated biochemically as is Menkes disease. We report a case of OHS in a 34-year-old male, which we believe to be the first Japanese case. He had been noted to have psychomotor retardation since his early childhood and now presents severe psychomotor retardation and muscle atrophy. He shows characteristic facial appearance, hyperelasticity of the skin, joint subluxation and generalized muscular atrophy. Laboratory investigations revealed a low serum copper and ceruloplasmin level as well as intestinal non-absorption of copper. Radiologic imagings showed occipital exostoses and bladder diverticula. The activity of lysyl oxidase, a copper-dependent enzyme involved in cross-link formation in collagen, was decreased in a skin-biopsied specimen. Electronmicroscopic investigation of a muscle biopsy showed irregularity of the myofibrillar network and accumulation of the concentric laminated bodies in the subsarcolemmal regions.