Expression of membrane antigens in myotonic dystrophy

Muscle biopsies from a series of myotonic dystrophy patients were analysed for expression of the nerve regulated gene products neural cell adhesion molecule (N-CAM) and 5.1H11. All eight biopsy specimens tested strongly expressed N-CAM and 5.1H11 as assessed by indirect immunofluorescence analysis. These results can be compared with those of Renaud et al (Nature, 1986;319:678) that show apamin binding to be a good marker of myotonic dystrophy muscle membranes. We suggest that in myotonic dystrophy a number of nerve regulated membrane markers are precociously expressed by innervated myofibres and that these are likely to be secondary manifestations resulting from an unidentified primary defect.