UNUSUAL EXPRESSION AND VERY MILD COURSE OF XP21 MUSCULAR-DYSTROPHY (BECKER TYPE) IN A 60-YEAR-OLD MAN WITH 26-PERCENT DELETION OF THE DYSTROPHIN GENE

A 54-year-old farmer with a negative family history had had mild proxi mal weakness for the previous 4 years. Clinical examination showed mar ked scoliosis, barrel-shaped chest, diffuse hypotrophy, and mild proxi mal weakness. Creatine kinase was 938 U/l; electrocardiography and ech ocardiography were normal. EMG disclosed myopathic changes. Muscle bio psy showed slight, nonspecific alterations. Dystrophin was present and normally distributed with antibodies against the C-terminal and N-ter minal, whereas it was not recognized by the antibody against the rod d omain. Western blotting detected an abnormal molecular weight protein of 320 kd (normal, 427 kd). Southern blot analysis revealed a deletion from exon 21 to exon 44, corresponding to 26% of the coding region of dystrophin. Six years' follow-up did not disclose progression of the muscle disease.