Question

What do you mean by congenital diseases? Give one example.

Answer 1

Hint: A disease is an abnormal state of the body that leads to disorders in the structure or function of the body. This disorder of body function is not associated directly with any external injury. For instance an accident leading to a fracture in a bone cannot be called a disease. A disease can be of many types based on its cause, like a deficiency disease, communicable disease, congenital disease etc.

Complete answer:
Congenital diseases are birth defects i.e. inborn diseases in terms of structural or physiological deformities. They are diseases which are developed inside the fetus during pregnancy or intrauterine life. Most of the congenital diseases are genetic defects which are inherited from the parental genes into the fetus but many other causes are associated with the development of congenital diseases.
Reasons for the development of congenital diseases:
1. Chromosomal abnormalities - Such abnormalities are associated with the error in the total chromosomes of the fetus which have been resulted from defects during gametogenesis. In other words when defected gametes having fewer or more chromosomes fertilize they produce a zygote which will develop a chromosomal abnormality and a congenital disease. Example- Down’s syndrome.
2. Gene defects - Gene defects inherited from parents to their children are congenital diseases. Example- Hemophilia, Sickle cell anemia.
3. Teratogens - Teratogens are substances in the environment around the fetus which leads to structural deformities in the children taking birth. Example - Thalidomide is a teratogen which causes deformities in the limbs of the fetus.
Other causes.
The second part of the question asks about examples of congenital diseases. Any one of the examples can be cited - Edward’s syndrome, Turners syndrome, Phenylketonuria etc.

Note:
Congenital diseases may be the result of a malfunction (deformation) of one or more body parts in the early stages of pregnancy or pressure on a body part (deformities) in the later stages of pregnancy. Intrauterine infections that do not cause structural defects (such as congenital syphilis) and recent acute strokes (such as hypoxia during childbirth) are generally not considered congenital diseases. Most congenital diseases are diagnosed during pregnancy but some are diagnosed after birth.