IMMUNOHISTOCHEMICAL STUDY OF MEROSIN-NEGATIVE CONGENITAL MUSCULAR-DYSTROPHY - LAMININ ALPHA-2 DEFICIENCY IN SKIN BIOPSY

We studied the immunohistochemical expression of laminin subunits alph a 2, alpha 1, beta 1 in muscle and skin biopsy samples from three pati ents with congenital muscular dystrophy (CMD), and from ten control pa tients investigated for various neuromuscular disorders. Merosin alpha 2 chain was not detectable in the basement membrane of muscle fibers, or in the nerve endings, cutaneous nerves, and cerium in the skin of the CMD patients, whereas it was clearly expressed in the skin biopsy samples from control patients, especially in the nerve endings of the arrector pill muscles. Laminin alpha 1 chain was expressed in the ceri um, in the muscle fiber membranes of arrector pill muscles and in cuta neous nerve fibers, perineurium and blood vessels in controls and in C MD patients, Laminin beta 1 chain was faintly expressed in the cerium, and a diffuse labeling was detected on arrector pill muscle with enha nced expression at nerve endings, intracutaneous nerves and capillarie s, with similar findings in all biopsy specimens. For merosin-negative CMD patients, skin biopsy may provide a diagnostic alternative to mus cle biopsy since merosin deficiency can be demonstrated in the skin ne ural structures, and in particular in the nerve endings of the arrecto r pill smooth muscles.