High resolution magnetic resonance imaging of the brain in the dy/dy mousewith merosin-deficient congenital muscular dystrophy

Magnetic resonance imaging (MRI) abnormalities in the cerebral white matter are a consistent feature of merosin-deficient human congenital muscular dy strophy, a disease caused by a primary defect in the expression of the lami nin alpha 2 chain of merosin. To investigate the relationship between imagi ng changes and merosin deficiency we undertook a MRI study in the dy/dy mou se, an animal model for this form of human congenital muscular dystrophy. H igh resolution in vivo imaging was performed on anaesthetized animals (two homozygous dy/dy mutants and two heterozygous dy/DY controls, aged 2.5 mont hs) in a dedicated 11.7T magnetic resonance imaging scanner. T-1 and T-2 we ighted images were normal in ail mice and white matter changes were not see n at a stage of maturity when MRI changes are already very striking in huma n patients. Cerebral MRI abnormalities do not appear toe a feature of dy/dy mice, despite the virtual absence of merosin expression in the dy/dy mouse brain. Possible causes for this absence of MRI changes, and implications f or the pathogenesis of the MRI changes in humans are reviewed. (C) 2000 Els evier Science B.V. All rights reserved.