Cat Eye Syndrome
Cat eye syndrome or Schmid–Fraccaro 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. There is no significant reduction in life expectancy in patients who are not afflicted with one of CES' life-threatening abnormalities.
Signs and symptoms
- Unilateral or bilateral iris coloboma (absence of tissue from the colored part of the eyes)
- Preauricular pits/tags (small depressions/growths of skin on the outer ears)
- Anal atresia (abnormal obstruction of the anus)
- Downward-slanting Palpebral fissures (openings between the upper and lower eyelids)
- Cleft palate
- Kidney problems (missing, extra, or underdeveloped kidneys)
- Short stature
- Scoliosis/Skeletal problems
- Cardiac defects (such as TAPVR)
- Micrognathia (smaller jaw)
- Hernias
- Biliary atresia
- Rarer malformations can affect almost any organ
- Intellectual disability – many are intellectually normal; about 30% of CES patients have moderately impaired mental development, although severe intellectual disability is rare.
The term "cat eye" syndrome was coined because of the particular appearance of the vertical colobomas in the eyes of some patients. However, over half of the CES patients in the literature do not present with this trait.
Genetics
The additional chromosome 22 usually arises spontaneously. It may be hereditary and parents may be mosaic for the marker chromosome but show no phenotypic symptoms of the syndrome.
The chromosomal area included in the cat eye syndrome "critical region" is 22pter→q11.
History
The abnormalities common to cat eye syndrome were first cataloged in 1899. 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.
See also
- Trisomy 22