De novo mutation in DMD gene in a patient with combined hemophilia A and Duchenne muscular dystrophy.

We report an unusual case of a patient with two combined X-linked diseases, severe hemophilia A (HA) and Duchenne muscular dystrophy (DMD), of which only HA was hereditary. There was no family history of muscular dystrophy. Genetic analysis revealed that HA was caused by the hereditary coagulation factor VIII (F8) intron 22 inversion (distal/type I inversion), whereas DMD was caused by a de novo deletion in the dystrophin gene. This is the first report of a patient with two severe X-linked diseases, of which only HA was hereditary. Despite the fact that the probability of acquiring two X-linked abnormalities, one hereditary and one de novo, is extremely low, the emergence of such cases indicates that genetic testing for distinct X-linked diseases could be of importance in patients with hereditary hemophilia.