Down syndrome (an additional 21 somatic chromosomes), its manifestations are the characteristic appearance of the child, mental retardation, multiple congenital disorders of organs and systems. More often, children with Down syndrome are born in age-old mothers who may have mutations in their eggs, but in most cases the cause of this disease remains unknown.
Phenylketonuria (changes in 12 pairs of somatic genes). This disease leads to the accumulation of an excess of phenylalanine in the human body, which leads to the development of mental retardation.
Also hereditary diseases include albinism (congenital lack of pigmentation of the skin, hair and iris of the eye), sickle cell anemia (the formation of sickle-shaped red blood cells that are not able to carry oxygen normally), hemophilia (blood clotting disorder), Wilson-Konovalov’s syndrome (impaired copper metabolism in organism). Such diseases are hereditary and are transmitted from sick parents to the child. More often, such diseases are associated with the X chromosome and occur in boys, girls are carriers of genes and transmit the disease to their children, but the disease themselves may not manifest themselves.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.