DMD and progressive muscular dystrophy: However, an early onset progressive muscular dystrophy could be seen in carriers with 45 X, 46 XY, and mosaic Turner karyotypes, apparently balanced X/autosome translocations with breakpoints in Xp21 within the dystrophin gene, and preferential inactivation of the normal X and nonrandom (skewed) X-chromosome inactivation that leads to diminished expression of the normal dystrophin allele [17, 22, 23].