Congenital muscular dystrophy: use of brain MR imaging findings to predict merosin deficiency.

Abstract

To evaluate the brain magnetic resonance (MR) imaging findings in patients with the "classic" form of congenital muscular dystrophy (patients with normal intelligence) in relation to the absence of merosin, a recently identified molecular component in the basement membrane of muscle fiber. Brain MR images in 15 patients (13 children, two adults) were reviewed and correlated with the patient's merosin status. Merosin was evaluated by means of immunocytochemical study of specimens from muscle biopsy. Nine patients had merosin deficiency. All patients had diffuse white matter alterations similar to those seen in cases of leukodystrophy. Periventricular and subcortical white matter were involved. The corpus callosum and internal capsule were spared. Follow-up MR images were available in two patients; changes were nonprogressive. White matter signal intensity was normal in the six patients with normal uniform labeling against merosin. Ventricular dilatation and cortical atrophy were observed in both groups. Diffuse white matter changes resembling those seen with leukodystrophy may be a valuable criterion for diagnosis of merosin deficiency in patients with classic congenital muscular dystrophy.