DYSTROPHIN EXPRESSION IN DUCHENNE PATIENTS WITH IN-FRAME GENE DELETIONS

Details of disease progression and dystrophin expression are presented for three patients with Duchenne muscular dystrophy (DMD) who unexpec tedly had intragenic deletions which maintained the open reading frame for mRNA translation. Analysis of dystrophin in muscle biopsies showe d variable dystrophin synthesis in all three patients. Two with relati vely small deletions (missing exons 10-13 and 52-55) had low levels of dystrophin which were comparable to those found in many DMD patients. The third patient (with a larger deletion which removed exons 3-25) p roduced dystrophin in the high abundance which is normally associated with patients who have Becker muscular dystrophy. This is the first ti me that a patient has been described with the clinical phenotype of DM D, a large amount of dystrophin which was correctly localized at the p eriphery of muscle fibres and an in-frame deletion of exons in the ami no terminal domain.