Molecular basis for three X-linked immune disorders.
Gene defects causing three X-linked human immunodeficiencies, agammaglobulinemia (XLA), hyper-IgM syndrome (HIGM), and X-linked severe combined immunodeficiency (SCID), have been identified. These represent the first human disease phenotypes associated with three gene families already recognized to be important in lymphocyte development and signaling: XLA is caused by mutations of a B-cell specific intracellular tyrosine kinase; HIGM by mutations in the tumor necrosis factor-related CD40 ligand, through which T cells deliver helper signals by direct contact with B-cell CD40; and SCID by mutations in the gamma chain of the lymphocyte receptor for interleukin-2. The great variety of patient mutations in all three genes represent both a challenge for genetic diagnosis and a resource for dissecting molecular domains and physiologic functions of the gene products.
Immunological Genetics Section, National Center for Human Genome Research, Bethesda, MD 20892.
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D002874:Chromosome Mapping; D005091:Exons; D008040:Genetic Linkage; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000235:genetics*; D014960:X Chromosome