Retrospective diagnosis of X-linked hyper-IgM syndrome in a family with multiple deaths of affected males.

All males in two generations of a Hungarian family died of interstitial pneumonia. History and records suggested X-linked hyper-IgM syndrome (X-HIGM). DNA sequencing of a female carrier revealed a c. 654C->A transversion of the CD40L gene that predicts premature termination of CD40L synthesis. This report points to the importance of early carrier detection and genetic counseling in families with X-linked primary immunodeficiency diseases. We propose that the c.654C->A sequence variant may associate with severe X-HIGM phenotype.