Duchenne muscular dystrophy in a female with 45,X/46,XX chromosome constitution

The case report is that of a 23-year-old female who suffered from Duchenne muscular dystrophy (DMD). Her maternal male cousin had classic DMD and her mother showed evidence of being heterozygous for the DMD gene. By using cultured skin fibroblasts and Epstein-Barr virus transformed lymphoblastoid cell line, her karyotype was identified to be a mosaic, 45,X/46,XX. Three previously reported cases with 45,X/46,XX manifested both DMD and Turner's syndrome, while the present case showed no clinical features of Turner's syndrome. No clinical features of Turner's syndrome may be related to the fact that the majority of lymphocytes and fibroblasts had 46,XX. On the other hand, it is considered that the paternal X chromosome has been preferentially lost by postzygotic non-disjunction and that the DMD gene from the maternal X chromosome is manifested in muscle cells.