Pitfalls in prenatal diagnosis of DMD due to placental mosaicism of the X-chromosomes: Prenatal and postnatal findings in a fetus with a deletion of exons 67-71 of the dystrophin gene

Prenatal diagnosis of Duchenne and Becker muscular dystrophy (DMD! is perfo rmed as a routine procedure in many laboratories. The major potential probl em is an incorrect diagnosis that could be obtained due to contamination wi th maternal tissue. We report a case of mosaicism of the X-chromosomes conf ined to the placenta as a possible source of confusing results in prenatal diagnosis of DMD. To the best of our knowledge, this is the first reported case of this problem in a prenatal DMD diagnosis. Copyright (C) 1999 John W iley & Sons, Ltd.