Diseases which are present from birth are called congenital diseases.
They are caused due to genetic abnormality or underdevelopment of any organ.
Most of these disorders are inherited from parents, and are not passed on from one person to another.
Some common examples are color-blindness, thalassemia and haemophilia.
In this condition the blood doesn't have the ability to clot and coagulate.
In thalassemia, the boudy produces less than normal quantity of red blood cells and haemoglobin.
It results in anaemia, which is addressed with frequent blood transfusions.
In this condition, the people are not able to see all colours, because the eyes don't contain all the pigments (cones) required for distinguishing colors.
Such people can lead a normal life but are banned from certain professions such as driving, working at traffic signals and becoming pilots.
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