1p36 deletion syndrome  is a congenital genetic disorder characterized by moderate to severe intellectual disability, delayed growth, hypotonia, seizures, limited speech ability, malformations, hearing and vision impairment, and distinct facial features. The symptoms may vary, depending on the exact location of the chromosomal deletion.The condition is caused by a genetic deletion (loss of a segment of DNA) on the outermost band on the short arm (p) of chromosome 1. It is one of the most common deletion syndromes. It is estimated that the syndrome occurs in one in every 5,000 to 10,000 births. Signs and symptoms
There are a number of signs and symptoms characteristic of monosomy 1p36, but no one individual will display all of the possible features. In general, children will exhibit failure to thrive and global delays. Developmental and behavioral
Most young children with 1p36 deletion syndrome have delayed development of speech and motor skills. Speech is severely affected, with many children learning only a few words or having no speech at all. Behavioral problems are also common, and include temper outbursts, banging or throwing objects, striking people, screaming episodes, and self-injurious behavior (wrist biting, head striking/banging). A significant proportion of affected people are on the autism spectrum, and many exhibit stereotypy. Neurologic
Most people with 1p36 deletion syndrome have some structural abnormality of the brain, and approximately half have epilepsy or other seizures. Almost all children exhibit some degree of hypotonia. Common structural brain abnormalities include agenesis of the corpus callosum, cerebral cortical atrophy, gait abnormalities, and ventriculomegaly.
Deuteranopic unilateral dichromats report that with only their deuteranopic eye open, they see wavelengths shorter than neutral point as blue and longer than it as yellow. Blue–yellow color blindness
Blue-yellow color blindness includes tritan CVD. Tritan CVD is related to the S-cone and includes tritanomaly (anomalous trichromacy) and tritanopia (dichromacy). Blue-yellow color blindness is much less common than red-green color blindness, and more often has acquired causes than genetic. Tritans have difficulty discerning between bluish and greenish hues. Tritans have a neutral point at 571 nm (yellowish). Tritan (<0.01% of individuals): Lacking, or possessing anomalous S-opsins or short-wavelength sensitive cone cells. Tritans see short-wavelength colors (blue, indigo and spectral violet) as greenish and drastically dimmed, some of these colors even as black. Yellow and orange are indistinguishable from white and pink respectively, and purple colors are perceived as various shades of red. Unlike protans and deutans, the mutation for this color blindness is carried on chromosome 7. Therefore, it is not sex-linked (equally prevalent in both males and females). The OMIM gene code for this mutation is 304000 "Colorblindness, Partial Tritanomaly". Tetartan is the "fourth type" of colorblindness, and a type of blue-yellow color blindness. However, its existence is hypothetical and given the molecular basis of human color vision, it is unlikely this type could exist. Summary of cone complements
The below table shows the cone complements for different types of human color vision, including those considered color blindness, normal color vision and superior color vision.