Genes of the Histamine Pathway and Common Diseases

Abstract

The review focuses on the functional role of histamine and the genetic factors involved in maintaining the physiological level of this amine in the organism, as well as on the involvement of histamine and genes of the histamine pathway in the development of several common diseases. Histamine is a biogenic amine with a wide range of competencies, the physiological effects of which are realized with the help of four types of receptors (HRH1, HRH2, HRH3, and HRH4), characterized by tissue-specific expression. The key genes responsible for maintaining the physiological level of histamine are HDC (responsible for the synthesis of endogenous histamine), AOC1, HNMT, MAOB, and ALDH7A1 (involved in the degradation of histamine and its metabolites). However, in total, according to Gene Ontology, proteins and enzymes encoded by more than 200 genes are involved in the histamine pathway. Both temporal and chronic imbalances between the synthesis/intake of histamine and its degradation/metabolism in the human body (including those caused by specific genetic features) mediate the development of inflammatory manifestations with disturbance of the homeostasis of various organ systems (nervous, immune, endocrine, cardiovascular, etc.). Immunopathologic reactions mediated by histamine accompany the development of antigen-specific and nonspecific immediate and delayed-type hypersensitivity reactions of inflammation, effector immunocomplex reactions, autoimmune disorders, and cancer and, ultimately, can determine the comorbidity of common diseases. The review also provides information on the associations of the genes of the histamine pathway with common diseases (according to the studies using the candidate-gene approach and genome-wide association studies).