X chromosome linked immunodeficiency.
Six human immunodeficiency diseases have been associated with the X chromosome by family studies. Genetic mapping with restriction fragment length polymorphisms (RFLPs) has permitted assignment of these diseases to specific loci on the X chromosome. Each of the disease entities maps to a single locus, confirming that the diagnostic criteria describe single diseases. X-linked chronic granulomatous disease and Wiskott-Aldrich syndrome map to loci on the short arm of the X chromosome; X-linked severe combined immunodeficiency, X-linked agammaglobulinemia, X-linked immunodeficiency with hyper-IgM, and X-linked lymphoproliferative syndrome map to loci on the long arm. Lyon's hypothesis predicts that these X-linked immunodeficiencies may be detectable in carriers of the diseases as a result of X chromosome inactivation of the normal disease gene. Four of the immunodeficiency diseases, X-linked agammaglobulinemia, X-linked severe combined immunodeficiency (SCID), Wiskott-Aldrich syndrome, and X-linked chronic granulomatous disease, affect cellular development so that carriers have a monomorphic population of immunocytes. The specific immunocyte development affected in carriers varies according to the disease. Genetic mapping of the diseases, with a collection of informative RFLPs, provides a tool that permits probability-based prenatal diagnosis. Carrier detection complements the RFLP-based genetic mapping, serving to confirm X-linkage in carriers.
Schwaber
J
J
Center for Blood Research, Harvard Medical School, Boston, Massachusetts.
Rosen
F S
FS
D002874:Chromosome Mapping; D015342:DNA Probes; D004303:Dosage Compensation, Genetic; D005260:Female; D006580:Genetic Carrier Screening; D005819:Genetic Markers; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000145:classification / Q000175:diagnosis / Q000235:genetics*; D008126:Lod Score; D008297:Male; D012150:Polymorphism, Restriction Fragment Length; D011296:Prenatal Diagnosis; D014960:X Chromosome
D015342:DNA Probes; D005819:Genetic Markers