Laminin α 2 (merosin)-deficient muscular dystrophy and demyelinating neuropathy in two cats

We report laminin alpha2 (merosin) deficiency associated with muscular dystrophy and demyelinating neuropathy in two cats. The cats developed progressive muscle weakness, and atrophy. Either hypotonia or contractures resulted in recumbency, necessitating euthanasia. Muscle biopsies showed dystrophic changes including marked endomysial fibrosis, myofiber necrosis, variability of fiber size, and perimysial lipid accumulation. Immunohistochemistry showed that laminin alpha2 chain was absent or reduced, while dystrophin and all the components of the dystrophin-associated glycoprotein complex were present and normal. One cat was examined in detail. Motor nerve conduction velocity (MNCV) was decreased, and ultrastructurally the peripheral nerves showed Schwann cell degeneration and demyelination. Brain imaging was not performed, but white matter changes were trot apparent in the brain at necropsy. The disease in these cats is similar to primary or secondary merosin (laminin alpha2)-deficient congenital muscular dystrophy (CMD) in humans and to dystrophia muscularis in mice. (C) 2001 Elsevier Science B.V. All rights reserved.