The Genetic Disease - Color Blindness
Color blindness, a condition where sufferers have the inability to distinguish between different colors or shades of color. This disease is an inherited disorder. The most common type of color blindness is genetic red-green color blindness, where the sufferers are unable to distinguish between green and red in dim light. Complete color blindness is a very rare condition, the victims are only able to determine black, white and shades of gray.
There are many types of genetic color blindness. For example, people who have the inability to distinguish any color variations have monochromatism, a condition of being completely color-blind. There are many other types of genetic color blindness that are less serious than monochromatism, such as protanopia, red-purple appears gray to the sufferers. Men have a much higher possibility of getting color blindness than women. This condition affects men much more frequently since color blindness is related to the X-chromosome, of which men have one, and women have two in every cell.
The gene that controls the ability to distinguish colors (such as red, green) is found only on the X-chromosome. The dominant allele of this gene produces normal color vision. However, people who have only the recessive allele are color-blind for red and green. The healthy X-chromosome in a woman would override the defectiveness of the other one. It is very unusual for both of the X-chromosome in a woman to be defective. As a result, the son of the woman who carries the gene has a 50 per cent chance of being color-blind. About 8 per cent of men will have a color vision problem. However, the daughter of the woman will not normally be color-blind, unless her mother carries the allele for color blindness and her father is color-blind. Less...