X-linked hyper-IgM syndrome (XHIM) is a rare primary immunodeficiency disorder, caused by mutations of the gene encoding CD40 ligand (CD40L; CD154). We report the clinical manifestations and mutational analysis of the CD40L gene observed in a male patient from a XHIM family. Having hypogammaglobulinemia and elevated IgM, the 3-yr-old boy exhibited the characteristic clinical features of XHIM. The patient suffered from frequent respiratory infections, and chronic enteritis caused by Cryptosporidium parvum. In addition, a lymph node biopsy and a culture from this sample revealed C. neoformans infection. Activated lymphocytes from the patient failed to express CD40L on their surface as assessed by flow cytometry and a missence mutation (W140R) was found at the XHIM hotspot in his CD40L cDNA to confirm the diagnosis. Genetic analysis of the mother and sister showed a heterozygote pattern, indicating carrier status. To our knowledge, this is the first report on the molecular diagnosis of an XHIM patient in Korea.
Animals ; CD40 Ligand/*genetics ; Child, Preschool ; Cryptococcosis/*complications/genetics/immunology ; Cryptococcus neoformans ; Cryptosporidiosis/*complications/genetics/immunology ; *Cryptosporidium parvum ; Female ; *Heterozygote ; Humans ; Hypergammaglobulinemia/complications/*diagnosis/genetics/immunology ; Immunoglobulin M/*blood ; Korea ; Male ; Pedigree ; *X Chromosome