Familial disorder of the central and peripheral nervous systems with particular cytoplasmic lamellated inclusions in peripheral nerves, muscle satellite cells, and blood capillaries.

Four siblings of a family of 11 were afflicted with a predominant parkinsonian syndrome, pyramidal signs, intellectual deterioration, and peripheral neuropathy. Symptoms were noticed first when they were aged 8 years; the condition was slowly progressive. All presented similar clinical features of varying severity. Nerve and muscle biopsies of two patients exhibited inclusions of concentric lamellae 2 nm thick with a periodicity of 3.6 nm, in the cytoplasm of perineurial and Schwann cells, endothelial cells and pericytes of blood capillaries, and muscle satellite cells. These inclusions differ in their location and morphological features from other inclusions that have been described in nerve and muscle biopsies of many disorders. The features of these inclusions suggest that they may represent a storage deposit whose nature could not be determined. They may be a distinguishing morphological feature of a multisystem disorder which to our knowledge has not been identified previously.