PCR AND IMMUNOBLOT ANALYSES OF DYSTROPHIN IN BECKER MUSCULAR-DYSTROPHY

The dystrophin gene was examined by PCR analysis in 30 Japanese patien ts with Becker muscular dystrophy (BMD). Fifteen PCR of these patients had exon deletions, generally, less than three exons. Muscle biopsies were also performed in 20 BMD patients (10 with sequence deletions, a nd 10 without detectable sequence deletions) in order to correlate PCR findings with immunoblot and immunostaining data. A patchy, heterogen eous membrane immunostaining pattern of reduced intensity was found, i rrespective of the presence or absence of deletions. Immunoblotting st udies demonstrated dystrophin of low molecular mass and quantity in BM D patients with deletion mutations, while a low quantity of dystrophin with an apparent wild type molecular mass was observed in nearly half the BMD patients without detectable deletions. However, these dystrop hins were also found to have slightly abnormal molecular masses when t he standard electrophoresis time was prolonged. This suggests that imm unoblots and PCR data correlate well in patients with BMD. Additionall y, it is suggested that immunoblot assays can detect abnormalities in dystrophin in the absence of detectable PCR deletions.