Hereditary skin diseases

Most hereditary skin diseases have predominantly ectodermal and ecomodermal origin. The main group consists of monogenic autosomal dominant diseases, autosomal recessive dermatoses are less frequently observed, and a minor part is made up of the dermatoses linked to the sex, namely, with the X-chromosome. The most frequent are diseases characterized by a disturbance of keratinization, less common are dermatoses with connective tissue damage, increased photosensitivity( sensitivity to light), a violation of pigmentation, dysplasia, bullous epidermolysis and a number of other skin diseases. The main multifactorial diseases are psoriasis, vitiligo and diffuse neurodermatitis, whose frequency in the population is significantly higher compared with the above dermatoses.

Skin changes are also observed in chromosomal diseases, hereditary diseases of other organs and systems, primarily caused by disorders of various types of metabolism, as well as in congenital malformations. Although in these cases skin pathology is not the main one, knowledge of the symptoms of the lesion can be useful for recognizing the disease and estimating the prognosis. For example, the eruptive xanthoma can be considered a symptom of type IV hyperlipidemia;Syringoma with periorbital localization( around the eyes) - Down's disease. Multiple sebaceous tumor tumors, keratoacanthomas, tricholemmoma, neuromas, fibromas and other benign neoplasms, mainly located in the face, are often associated with tumors of the internal organs inherited in the autosomal dominant type. Pigmented spots of the color "coffee

with milk" or the centers of depigmentation( areas that do not contain the pigment at all) on the trunk, resembling a fern leaf, can be the first sign of neurofibromatosis and tuberous sclerosis, respectively. The presence of light skin, discolored hair can be a manifestation of Menkes syndrome or phenylketonuria, especially when combined with eczema-like dermatitis in the latter case. Diffuse hyperpigmentation( the deposition of a large amount of pigment in some parts of the skin, due to which the skin in this place acquires a darker color) requires the exclusion of hemochromatosis. Erythematoskamoznye rashes, located in the face, can be a symptom of a disturbance of the exchange of biotin. The combination of focal keratoses at the fingertips with keratitis, as a rule, is a sign of type II tyrosinemia. The presence in the child in the face or scalp of the head of the epidermal or fat-greasy nevus( "mole") serves as an indication for the consultation of a neurologist with a view to early detection of organic brain damage. Of great importance are syndromes in which chromosome instability is detected( for example, Bloom's syndrome), which is associated with the presence of a high risk of malignant diseases.

Data on the prevalence of hereditary skin diseases in various countries are few and difficult to compare because of differences in the approach to obtaining data. When studying the geography of hereditary dermatoses, in our country a similar level of burden is established in some regions of the Non-chernozem zone of Russia, Uzbekistan and Azerbaijan, with predominance of autosomal recessive diseases( albinism, lamellar ichthyosis) in Uzbekistan and Azerbaijan, and heritable autosomal dominant( simple ichthyosis, tuberoussclerosis) in the Non-Black Earth region. Many genetically caused skin diseases are genetically heterogeneous. Most of them exist already from the moment of birth or develop shortly after it, but a part( for example, Werner's syndrome) manifests clinically in adults.

With some hereditary skin diseases, localization of genes has been established, a primary biochemical defect has been identified, however, the mechanisms of development of the majority of hereditary skin diseases have not been clarified, nor have effective methods of treatment been developed. From the achievements of recent years, we can note the effectiveness of zinc preparations for enteropathic acrodermatitis and retinoids in diseases of keratinization. Prenatal( prenatal) diagnosis is still carried out with a relatively small number of genetically determined skin diseases, and the possibilities of detecting heterozygous carriage are limited.