M*
(as subscript), mutated M opsin. L*
(as subscript), mutated L opsin.The following table shows the pattern of inheritance for congenital red–green colorblindness (protan/deutan) given affected, unaffected or carrier parents. When daughter 1 and daughter 2 (or son 1 and son 2) differ, this indicates a 50% chance of each outcome. Some conclusions from the table include:

A male cannot inherit colorblindness from his father. A colorblind female must have a colorblind father. A female must inherit colorblindness alleles from both parents to be colorblind. Colorblind females can only produce colorblind males. Because carrier females often have a colorblind father, colorblind males often will have a colorblind maternal grandfather (or great grandfather). In this way, colorblindness is often said to skip a generation.Note: these conclusions do not apply to other forms of colorblindness (e.g. tritanopia). Genetics of blue–yellow color blindness
Blue-yellow color blindness is a rarer form of colorblindness including tritanopia/tritanomaly. These conditions are mediated by the OPN1SW gene on Chromosome 7. Other genetic causes
Several inherited diseases are known to cause color blindness:

achromatopsia(also called rod monochromatism, stationary cone dystrophy or cone dysfunction syndrome)
cone dystrophy
cone-rod dystrophy
Lebers congenital amaurosis
retinitis pigmentosa(initially affects rods but can later progress to cones and therefore color blindness).They can be congenital (from birth) or can commence in childhood or adulthood. They can be stationary, that is, remain the same throughout a persons lifetime, or progressive. As progressive phenotypes involve deterioration of the retina and other parts of the eye, many of the above forms of color blindness can progress to legal blindness, i.e.
A cone monochromat can have good pattern vision at normal daylight levels, but will not be able to distinguish hues. Cone monochromacy is divided into classes defined by the single remaining cone class. However, red and green cone monochromats have not been definitively described in the literature. Blue cone monochromacy is caused by lack of functionality of L (red) and M (green) cones, and is therefore mediated by the same genes as red–green color blindness (on the X chromosome). Peak spectral sensitivities are in the blue region of the visible spectrum (near 440 nm). People with this condition generally show nystagmus ("jiggling eyes"), photophobia (light sensitivity), reduced visual acuity, and myopia (nearsightedness). Visual acuity usually falls to the 20/50 to 20/400 range. Dichromacy
Dichromats can match any color they see with some mixture of just two primary colors (in contrast to those with normal sight (trichromats) who can distinguish three primary colors). Dichromats usually know they have a color vision problem, and it can affect their daily lives. Dichromacy in humans includes protanopia, deuteranopia, and tritanopia. Out of the male population, 2% have severe difficulties distinguishing between red, orange, yellow, and green. (Orange and yellow are different combinations of red and green light.) Colors in this range, which appear very different to a normal viewer, appear to a dichromat to be the same or a similar color. The terms protanopia, deuteranopia, and tritanopia come from Greek, and respectively mean "inability to see (anopia) with the first (prot-), second (deuter-), or third (trit-) [cone]".