Color blindness genetics

What Do You Know about Color Blindness

Color blindness or more accurately color vision deficiency isa condition affecting the person’s perception of colors. There are somediscrepancies in the way these people see colors. The problems might be verymild, 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. Peoplewith color vision deficiency are not blind, you should know that. However, thecondition itself is not treatable and there are no cures for the problem.

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

Types of Color Blindness

There are several types of color blindness, including: partialcolor blindness such as red-green and blue-yellow color vision defects andalso total color blindness. About 99% of people suffering from color deficiencycan’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 totalabsence of color vision is very rare. This condition, when a person can’t visualizeany color is known as achromatopsia. Only colors these people can perceive areblack, white and various shades of gray. Reduced visual acuity, involuntary eyemovements (nystagmus) and photophobia may also be present in people sufferingfrom achromatopsia.

Color Blindness Genetic Base

Color blindness was the first of genetic condition that wasidentified and then linked to a specific chromosome. Scientists now know that changesin different chromosomes provoke different types of color vision deficiency. Thereare also color blindness patients that never inherited the condition, but whoseproblem is associated with the use of some medications such as Plaquenil (rheumatoidarthritis drug) after birth.

As many genetic conditions color vision deficiency is linkedto the gene present on X chromosome and because of that it is known as the Xlinked inheritance. Color blindness is not inherited from the father, butrather from a mother of a child. That means that color blind father doesn’t necessarilyhave to give the condition to his son. Women are carriers of the genes but theydon’t express the disorder, but their sons do inherit the gene and can sufferfrom 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 theprobability that an offspring will exhibit some specific genetic trait and sufferfrom some condition.