Background: The X-linked hyper-IgM (XHIM) syndrome is a rare form of primary immunodeficiency disorder characterized by hypogammaglobulinemia and impaired cell immunity.
Observation: We report history of Guianese family affected by XHIM syndrome. The eldest boy died at 7 months from pneumonia. The 5-month-old youngest boy presented with a potentially fatal episode of Pneumocystis jiroveci pneumonia. The diagnosis was done in the Pediatric Unit of Immunohematology of Hopital Necker in Paris.
Conclusions: This report points to the importance of diagnosis of XHIM to allow early treatment to minimize serious infections and to detect carriers in XHIM families for genetic counseling.