The distal part of the human dystrophin gene is characterised by
particular features and seems to play an important functional role.
Additionally in recent years several data have implicated minor
mutations in this gene region in some patients,vith mental retardation
(MR), In order to screen for pathogenic mutations at the distal part of
the human dystrophin gene we have used 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 revealed
six different and pathogenic minor changes, five in DMD and one in a BMD
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 interesting similarity with part of the 3’ end of the genome of
eastern equine encephalomyelitis virus (EEEV). The present data from
Greek DMD/BMD patients give further information about the phenotypic
effects consequent on mutations in exons at the distal part of the human
dystrophin gene