Early Ultrastructural Changes in the Central Nervous System in Fukuyama Congenital Muscular Dystrophy

Electron microscopy of the central nervous system surface structure is described in two fetuses with Fukuyama congenital muscular dystrophy (FCMD). In addition to relatively large surface defects, many minute defects less than several micrometers in size associated with protrusion of glial cytoplasm were observed in the cerebrum. These findings were considered to represent early changes prior to cortical dysplasia. The basement membrane adjacent to the defects showed amorphous, wavy, or whorled configurations, and gradually disappeared. The glial cytoplasmic membrane seemed to be relatively well preserved in some areas where the basement membrane disappeared. On the other hand, both the basement membrane and cytoplasmic membrane became indistinct irregularly in areas without defects, including the spinal cord; similar lesions were found in the skeletal muscle. These observations confirm previous observations concerning defects of the pial-glial barrier of the brain surface, and may suggest the involvement of abnormal basement membrane or related structures, or both, in the genesis of the brain lesions of FCMD.