Screening for minor changes in the distal part of the human dystrophin gene in Greek DMD/BMD patients

The distal part of the human dystrophin gene is characterised by particular features and seems to play an important functional role. Additionally in r ecent years several data have implicated minor mutations in this gene regio n in some patients,vith mental retardation (MR), In order to screen for pat hogenic mutations at the distal part of the human dystrophin gene we have u sed single-strand conformation analysis of products amplified by polymerase chain reaction (PCR-SSCA) in 35 unrelated male Greek DMD/BMD patients with no detectable deletions. Seven patients also had severe mental retardation . Direct sequencing of samples demonstrating a shift of SSCA mobility revea led six different and pathogenic minor changes, five in DMD and one in a BM D patient. Four of the mutations were found in DMD patients,vith severe MR. Three of these mutations were localised in exon 66,,which presents an inte resting similarity with part of the 3' end of the genome of eastern equine encephalomyelitis virus (EEEV). The present data from Greek DMD/BMD patient s give further information about the phenotypic effects consequent on mutat ions in exons at the distal part of the human dystrophin gene.