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Color blindness genetics

What Do You Know about Color Blindness

Color blindness or more accurately color vision deficiency is a condition affecting the person’s perception of colors. There are some discrepancies in the way these people see colors. The problems might be very mild, when the affected person can’t recognize the shade of the certain color, but there are also people completely unable to detect any color whatsoever. People with color vision deficiency are not blind, you should know that. However, the condition itself is not treatable and there are no cures for the problem.

Another name for color vision deficiency is Daltonism, given after the name of a man who described this condition, John Dalton. Color blindness is much more common among men than women and it is estimated that there is just 0.5% of women suffering from this vision problem.

Types of Color Blindness

There are several types of color blindness, including: partial color blindness such as red-green and blue-yellow color vision defects and also total color blindness. About 99% of people suffering from color deficiency can’t distinguish red or green color. More of them can’t see green properly (about 75% of them). Blue-yellow color vision deficiency is rarer, while total absence of color vision is very rare. This condition, when a person can’t visualize any color is known as achromatopsia. Only colors these people can perceive are black, white and various shades of gray. Reduced visual acuity, involuntary eye movements (nystagmus) and photophobia may also be present in people suffering from achromatopsia.

Color Blindness Genetic Base

Color blindness was the first of genetic condition that was identified and then linked to a specific chromosome. Scientists now know that changes in different chromosomes provoke different types of color vision deficiency. There are also color blindness patients that never inherited the condition, but whose problem is associated with the use of some medications such as Plaquenil (rheumatoid arthritis drug) after birth.

As many genetic conditions color vision deficiency is linked to the gene present on X chromosome and because of that it is known as the X linked inheritance. Color blindness is not inherited from the father, but rather from a mother of a child. That means that color blind father doesn’t necessarily have to give the condition to his son. Women are carriers of the genes but they don’t express the disorder, but their sons do inherit the gene and can suffer from color blindness.

For those interested in genetic probability and inherited disorders, there is a Punett square. This is the device helpful for the prediction of the probability that an offspring will exhibit some specific genetic trait and suffer from some condition.

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