DYSTROPHIN EXPRESSION IN A DUCHENNE MUSCULAR-DYSTROPHY PATIENT WITH AFRAME-SHIFT DELETION

The exon 45 deletion is a common dystrophin gene deletion. Although th is is an out-of-frame deletion, which should not allow for protein syn thesis, it has been observed in mildly affected patients, We describe a patient with an exon 45 deletion who produced protein, but still had a severe Duchenne muscular dystrophy phenotype, RT-PCR analysis and c DNA sequencing from the muscle biopsy sample revealed that the exon 45 deletion induced exon skipping of exon 44, which resulted in an in-fr ame deletion and the production of dystrophin. A conformational change in dystrophin induced by the deletion is proposed as being responsibl e for the severe phenotype in the patient. We feel that the variable c linical phenotype observed in patients with the exon 45 deletion is no t due to exon splicing but, may be the result of other environmental o r genetic factors, or both.