Fukuyama Type Congenital Progressive Muscular Dystrophy (FCMD) – Special Comment on the Relationship Between the Case Reported by Nakayama et a1 and FCMD –

A case of Fukuyama-type congenital muscular dystrophy with a very mild mental deficit

A boy had the clinical features of congenital muscular dystrophy with a very mild mental deficit. A muscle biopsy at one year of age showed the typical findings of Fukuyama-type congenital muscular dystrophy, including selective loss of immunoreactions for alpha dystroglycan. Magnetic resonance imaging showed no findings suggestive of migration disorders. The diagnosis of Fukuyama-type congenital muscular dystrophy was confirmed by a molecular assay at 8 years of age, and his haplotype analysis was heterozygous. At 9 years of age, his FIQ on the Wechsler Scale for Children revealed 69, while his IQ on the Tanaka Binnet scale of intelligence was 97. In this report the relationship between mild clinical condition of the studied case and its genotype is discussed.

Immature astrocytes in Fukuyama congenital muscular dystrophy: an immunohistochemical study

Recent studies of Fukuyama congenital muscular dystrophy have focused on abnormalities of the basement membrane in muscle and brain. The cerebral cortex has a unique basement membrane at the glia limitans, which is intimately related to astrocytes in the developing brain, and the basement membrane may be partially produced by the astrocyte. In this study the cerebral astrocytes in six patients with Fukuyama congenital muscular dystrophy, including two fetal patients, were characterized by immunohistochemical study. In fetal Fukuyama congenital muscular dystrophy, astrocytes reacted less to antibodies of glial fibrillary acidic protein, S-100 protein, and alphaB-crystallin than control astrocytes, but in postnatal Fukuyama congenital muscular dystrophy, astrocytes reacted more to these antibodies and displayed beading of processes. Moreover, vimentin was positive in the astrocytes of two postnatal Fukuyama congenital muscular dystrophy patients. This astrocytic appearance may suggest immaturity of astrocytes in Fukuyama congenital muscular dystrophy. Astrocytes exhibiting beaded cytoplasmic processes were prominent at the subpia of the cortex and around vessels. The authors hypothesize that these immature astrocytes are unable to participate in the function of the cortical basement membrane, which is defective in Fukuyama congenital muscular dystrophy. Studies of neurons and meninges were similar to those of control subjects.

Pial-glial barrier abnormalities in fetuses with Fukuyama congenital muscular dystrophy

This report concerns light and electron microscopic studies on the central nervous system of a 20-week and an 18-week fetus with Fukuyama congenital muscular dystrophy (FCMD). The diagnosis of FCMD was established by prenatal molecular genetic analysis. Cerebral lesions containing neurites, subpial granular cells and glias, accompanied by cortical dysplasia were found in both cases. Small irregular defects, readily detectable by periodic acid-methenamine-silver staining or by immunohistochemical staining for S-100 protein, were observed in the cerebral surface. More severe dysplasia was evident at the areas with the larger defects. Surface defects were also observed in the cerebellum and brain stem, with brain tissue extruding into the leptomeninges. The pyramidal tract was aberrant in the pons and medulla oblongata. The spinal cord appeared normal by light microscopy. Electron microscopic examination revealed an abnormal configuration of the basement membrane and glial cytoplasmic membrane of the brain and spinal cord surfaces, including areas with no detectable defects by light microscopy. These findings suggest that abnormalities of the pial-glial barrier, especially the basement membrane and/or basement membrane-related structures, are involved in the genesis of cortical dysplasia.