Patterns of dystrophin gene deletions in DMD/BMD patients were compared in four populations: Turks (n = 146 deletions), Europeans (n = 838), North Indians: (n = 89), and Indians from all over India (n = 103). Statistical tests revealed that there are differences in the proportions of small deletions. In contrast, the distribution of deletion breakpoints and the frequencies of specific deletions commonly observed in the four populations are not significantly different. The variations strongly suggest that sequence differences exist in the introns; and the differences are in agreement with genetic distances among populations. The similarities suggest that some intronic sequences have been conserved and that those will trigger recurrent deletions, since it is unlikely that gene flow would disperse the deleted chromosomes. which vanish from the gene pool in a few generations.