Prenatal diagnosis of X-linked hyper-IGM syndrome by direct detection of mutation Q220X in the CD40L gene using PCR-mediated site directed mutagenesis.

We present the first report of prenatal diagnosis of X-linked hyper-IgM syndrome by PCR-mediated site directed mutagenesis (PSM) in a woman known to carry the Q220X mutation in the CD40L gene. Using the simple PSM assay, the Q220X mutation was identified by chorionic villous sampling (CVS) at 11 weeks' gestation and the pregnancy was terminated.