List Diseases – X
Xerophthalmia (xerotic keratitis, keratomalacia) is a degeneration of the cornea caused by a nutritional deficiency.
Xanthoma of the skin, in particular multiple tuberous xanthomas, is one of the manifestations of impaired lipid metabolism. An increase in the level of triglycerides and cholesterol in the blood plasma was found because of a disruption in the formation, transport and splitting of lipoproteins. Clinically distinguish eruptive, tuberous, tendon and flat xanthomas.
X-Linked Lymphoproliferative Syndrome (XLP) is a rare hereditary disease characterized by a violation of the immune response to the Epstein-Barr virus-EBV virus. XLP was first identified in 1969 by David T. Purtilo et al., Who observed a family in which boys died from infectious mononucleosis.
The lymphoproliferative syndrome linked to the X chromosome is the result of a defect of T-lymphocytes and natural killers and is characterized by an abnormal response to infections caused by the Epstein-Barr virus, leading to liver damage, immunodeficiency, lymphoma, fatal lymphoproliferative disease, or bone marrow aplasia.
More than 10 years ago, a gene was discovered whose mutations lead to the development of the HIGM1 form of the disease. In 1993, the results of five independent research groups were published showing that mutations in the gene of the CD40 ligand (CD40L) are a molecular defect underlying the Xt chained form of hyper-IgM syndrome. The gene encoding the gp39 (CD154) - CD40L protein is located on the long arm of the X chromosome (Xq26-27). The CD40 ligand is expressed on the surface of activated T-lymphocytes.
X-linked agammaglobulinemia is a disease that is accompanied by the development of a low level of immunoglobulins or their absence, which often leads to the development of recurrent infections.