Changes in cerebral white matter in a case of congenital muscular dystrophy (non-Fukuyama type)

Congenital muscular dystrophy. Part I: a review of phenotypical and diagnostic aspects

The congenital muscular dystrophies (CMDs) are a group of genetically and clinically heterogeneous hereditary myopathies with preferentially autosomal recessive inheritance, that are characterized by congenital hypotonia, delayed motor development and early onset of progressive muscle weakness associated with dystrophic pattern on muscle biopsy. The clinical course is broadly variable and can comprise the involvement of the brain and eyes. From 1994, a great development in the knowledge of the molecular basis has occurred and the classification of CMDs has to be continuously up dated. We initially present the main clinical and diagnostic data concerning the CMDs related to changes in the complex dystrophin-associated glycoproteins-extracellular matrix: CMD with merosin deficiency (CMD1A), collagen VI related CMDs (Ullrich CMD and Bethlem myopathy), CMDs with abnormal glycosylation of alpha-dystroglycan (Fukuyama CMD, Muscle-eye-brain disease, Walker-Warburg syndrome, CMD1C, CMD1D), and the much rarer CMD with integrin deficiency. Finally, we present other forms of CMDs not related with the dystrophin/glycoproteins/extracellular matrix complex (rigid spine syndrome, CMD1B, CMD with lamin A/C deficiency), and some apparently specific clinical forms not yet associated with a known molecular mechanism. The second part of this review concerning the pathogenesis and therapeutic perspectives of the different subtypes of CMD will be described in a next number.

Congenital muscular dystrophy: a review of the literature

Congenital muscular dystrophy (CMD) is a condition in which there are already at birth, marked hypotonia, generalized muscle weakness and frequently multiple contractures. CMD has recently been classified into four categories: CMD I, the classical or "pure' CMD without severe impairment of intellectual development; CMD II, the Fukuyama type CMD with muscle and structural brain abnormalities; CMD III and IV with muscle, eye and brain abnormalities; the milder Finnish type CMD (CMD III) and the severe Walker-Warburg syndrome (CMD IV). Data of the literature concerning those different CMD types have been reviewed and are presented with emphasis on signs and symptoms, clinical course, laboratory, neurophysiological, radiological, morphological and genetic characteristics.

Congenital muscular dystrophy with cerebral white matter hypodensity. Correlation of clinical features and merosin deficiency

We report clinical and pathological findings in 9 children affected by congenital muscular dystrophy with normal or borderline intelligence and hypodensity of cerebral white matter (CMD-HWM), also frequently called 'occidental or western form of cerebro-muscular dystrophy' (OCMD). Our patients have uniform, distinct, clinical presentation that includes: normal or subnormal intelligence, severe, slowly progressive motor disability, high rate of facial involvement and dysmorphic aspect, increased creatine kinase levels and variable degrees of abnormal, radiographic, cerebral white matter pattern. By comparing our cases with previous reports we suggest that this subtype of CMD is not uncommon in Brazil and it is represented by a particularly severe and homogeneous clinical picture with important motor disability. The immunohistochemical staining for merosin, performed on the muscle biopsy of 6 among 9 patients, showed that all are merosin negative.

White matter abnormalities in congenital muscular dystrophy

Central nervous system (CNS) characteristics were examined in seventeen patients with autosomal recessive classic or "pure" congenital muscular dystrophy (CMD). In three patients, neuroradiological examination (CT/MRI) indicated hypodense white matter areas. Two out of these three patients had epilepsy (seizures and epileptic discharges on their EEG). Only two of the remaining patients had epileptic EEG discharges, but without clinical seizures. By comparing our results to data in the literature, we could conclude that the classic or "pure" form of CMD can be subdivided into two subtypes, i.e. those with and those without white matter hypodensities. A mild form of epilepsy or an epileptic predisposition on EEG can be part of the subtype with white matter hypodensities.

Congenital muscular dystrophy with abnormal radiographic myelin pattern

We report 11 children with a homogeneous clinical syndrome affecting both sexes, characterized by weakness at birth, slowly improving course, weakness of all muscle groups, arreflexia, elevated blood creatine kinase, normal nerve conduction velocity, dystrophic changes on muscle biopsy, and diffuse periventricular cortical white-matter abnormalities with sparing of corpus callosum, internal capsule, and brain stem. We compare them to 48 other previously reported similar cases and designate them as altered myelin radiographic pattern congenital muscular dystrophy (CMD), which is the same as occidental CMD. We compare them to the other presently accepted phenotypes: progressive Fukuyama CMD, Walker-Warburg or cerebral-ocular CMD, and Santavuori or muscle-eye-brain CMD. We suggest that the different phenotypes are alleles of the same gene, which regulates or expresses a structural protein required for muscle integrity, myelination, and formation of the cortex. Such phenotypic diversity has been established for mutations of Xp21 in X-linked muscular dystrophies.