How often are genetic disorders in humans?

Genetic disorders are any physical or mental pathology that can be inherited from parents.
Diseases found at birth are called congenital. Some genetic disorders do not occur at birth, the disease develops as a person grows, his signs and symptoms appear. Pathology may remain unrecognized until a person reaches puberty or even until adulthood.
To understand genetic disorders, you need to know some basic terms of the science of genetics and the principles of inheritance.
– Birth defects are a popular term for diseases and pathologies associated with physical abnormalities, most of which are of a genetic nature. Nevertheless, the term “birth defect” sometimes refers to a pathology that is not caused by genetic disorders, or its use is unreasonably limited only to physical defects.
– The term “genetic” is associated with genes – the basic units of heredity. When discussing congenital physical or mental abnormalities, the term “genetic” refers to a pathology that occurs as a result of one or more disturbances in the structure of genes or chromosomes.
– The term “hereditary” refers to any characteristic of an individual that may be passed on to his or her descendants. Some genetic disorders, such as hemophilia (coagulation defect), are hereditary; others, such as Turner syndrome (impaired sexual development in women), are not. To say that this disease is genetic does not necessarily mean that it is hereditary and will be present in one or all of the descendants of this pair. In addition, some hereditary changes, such as birthmarks, are considered inherited, although in reality this is not always the case.
Genetic disorders are a universal problem. They are found in representatives of all races, ages, and both sexes. Some genetic disorders are nevertheless more common in certain ethnic groups. For example, sickle cell anemia (a rare defect in red blood cells) is more common among black children (1 in 600 newborns). Tay-Sachs disease (a rare fatal degenerative disease of the nervous system; occurs almost exclusively among Jews from Eastern Europe.
Every year in the United States, 1 out of 20 newborns shows a particular genetic defect. Many of them are insignificant, others represent the main cause of many violations. For example, it is estimated that 4 out of 5 mentally handicapped people in the United States are associated with various genetic defects. In addition, studies confirm that many diseases have a genetic component: a violation of the genetic material was discovered as the only or one of the reasons for the continued increase in the number of diseases in humans.
Each person carries on average one gene of a serious genetic disease that can be transmitted to posterity. According to geneticists, each couple has a 3% risk of having a baby with a genetic pathology or birth defect immediately after birth.
However, some defective genes determine only the predisposition to the disease, which manifests itself in the presence of certain environmental factors. One such factor is diet. Children with phenylketonuria, for example, cannot tolerate the usual amount of protein in their diet, as their body lacks a certain enzyme necessary for the complete metabolism of one of the protein components. With a normal diet, these children have a severe mental retardation. But if their protein intake is strictly limited and their diet is changed, these children develop normally.