List Diseases – X
Xerostomia is the medical term used to describe a condition in which a person has severely dry or dehydrated mucous glands, resulting in insufficient saliva production.
In medicine, xerosis refers to excessive dryness of the skin (from Greek xeros - dry), i.e. Insufficient hydration.
Xerophthalmia (xerotic keratitis, keratomalacia) is a degeneration of the cornea caused by nutritional deficiency.
Xeroderma pigmentosum is a hereditary disease, transmitted by an autosomal gene from parents, relatives and has a familial nature.
Skin xanthomas, in particular multiple tuberous xanthomas, are one of the manifestations of impaired lipid metabolism. An increase in the level of triglycerides and cholesterol in the blood plasma has been revealed due to a disorder in the formation, transport and breakdown of lipoproteins. Clinically, eruptive, tuberous, tendinous and flat xanthomas are distinguished.
X-linked lymphoproliferative syndrome (XLP) is a rare inherited disorder characterized by an impaired immune response to the Epstein-Barr virus (EBV). XLP was first identified in 1969 by David T. Purtilo et al., who observed a family in which boys died from infectious mononucleosis.
X-linked lymphoproliferative syndrome results from a defect in T-lymphocytes and natural killer cells and is characterized by an abnormal response to Epstein-Barr virus infections, leading to liver damage, immunodeficiency, lymphoma, fatal lymphoproliferative disease, or bone marrow aplasia.
More than 10 years ago, a gene was discovered, mutations in which lead to the development of the HIGM1 form of the disease. In 1993, the results of the work of five independent research groups were published, showing that mutations in the CD40 ligand gene (CD40L) are a molecular defect underlying the Xt-linked form of hyper-IgM syndrome. The gene encoding the protein gp39 (CD154) - CD40L, is localized 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 low levels of immunoglobulins or their absence, which often leads to the development of recurrent infections.