Cat eye syndrome
Encyclopedia
Cat Eye Syndrome is a rare condition caused by the short arm (p) and a small section of the long arm (q) of human
Chromosome 22 being present three (trisomic
) or four times (tetrasomic
) instead of the usual two times. The term "Cat Eye" syndrome was coined because of the particular appearance of the vertical coloboma
s in the eyes of some patients. However, over half of the CES patients in the literature do not present with this trait. There is no significant reduction in life expectancy
in patients who are not afflicted with one of CES' life threatening abnormalities.
symptoms of the syndrome
.
The chromosomal area included in the Cat Eye Syndrome "critical region" is 22pter→q11.
Human
Humans are the only living species in the Homo genus...
Chromosome 22 being present three (trisomic
Trisomy
A trisomy is a type of polysomy in which there are three copies, instead of the normal two, of a particular chromosome. A trisomy is a type of aneuploidy .-Description and causes:...
) or four times (tetrasomic
Tetrasomy
A tetrasomy is a form of aneuploidy with the presence of four copies, instead of the normal two, of a particular chromosome.-Full:Full tetrasomy of an individual occurs due to non-disjunction when the cells are dividing to form egg and sperm cells . This can result in extra chromosomes in a sperm...
) instead of the usual two times. The term "Cat Eye" syndrome was coined because of the particular appearance of the vertical coloboma
Coloboma
A coloboma is a hole in one of the structures of the eye, such as the iris, retina, choroid or optic disc...
s in the eyes of some patients. However, over half of the CES patients in the literature do not present with this trait. There is no significant reduction in life expectancy
Life expectancy
Life expectancy is the expected number of years of life remaining at a given age. It is denoted by ex, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience...
in patients who are not afflicted with one of CES' life threatening abnormalities.
Genetics
The additional chromosome 22 usually arises spontaneously. It may be hereditary and parents may be mosaic for the marker chromosome but show no phenotypicPhenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...
symptoms of the syndrome
Syndrome
In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...
.
The chromosomal area included in the Cat Eye Syndrome "critical region" is 22pter→q11.
History
The abnormalities common to to cat eye syndrome were first cataloged in 1898. It was described in association with a small marker chromosome in 1965. Early reports of Cat Eye Syndrome discuss the possibility of chromosome 13 involvement. Now, CES is considered to be present with the chromosome 22 trisomy findings.Characteristics
- Anal atresia (abnormal obstruction of the anus)
- Unilateral or bilateral irisIris (anatomy)The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
colobomaColobomaA coloboma is a hole in one of the structures of the eye, such as the iris, retina, choroid or optic disc...
(absence of tissue from the colored part of the eyes) - Palpebral fissures (downward slanting openings between the upper and lower eyelids)
- Preauricular pits/tags (small depressions/growths of skin on the outer ears)
- Cardiac defects (such as TAPVR)
- Kidney problems (missing, extra, or underdeveloped kidneys)
- Short stature
- ScoliosisScoliosisScoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an X-ray, viewed from the rear, the spine of an individual with scoliosis may look more like an "S" or a "C" than a straight line...
/Skeletal problems - Mental retardationMental retardationMental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
-- although most are borderline normal to mildly retarded, and a few even have normal intelligence, CES patients occasionally exhibit moderate to severe retardation. - Micrognathia (smaller jaw)
- HerniaHerniaA hernia is the protrusion of an organ or the fascia of an organ through the wall of the cavity that normally contains it. A hiatal hernia occurs when the stomach protrudes into the mediastinum through the esophageal opening in the diaphragm....
s - Cleft palate
- Rarer malformations can affect almost any organ