Cat eye syndrome

What causes cat eye syndrome?

Cat eye syndrome is most often caused by a chromosome abnormality called an inverted duplicated 22. In people with this condition, each cell has at least one small extra (duplicate) chromosome made up of genetic material from chromosome 22. This extra genetic material leads to the characteristic signs and symptoms of cat eye syndrome.

Last updated on 05-01-20

How is cat eye syndrome diagnosed?

A diagnosis of cat eye syndrome is often suspected based on the presence of characteristic signs and symptoms. Genetic testing can then be ordered to confirm the diagnosis. This testing may include:

  • Karyotype - a karyotype is a laboratory test that produces an image of a person's chromosomes.
  • FISH - a laboratory technique that is used to detect and locate a specific DNA sequence on a chromosome. During FISH, a chromosome is exposed to a small DNA sequence called a probe that has a fluorescent molecule attached to it. The probe sequence binds to its corresponding sequence on the chromosome.

In some cases, cat eye syndrome can be diagnosed before birth. If suspicious features are observed on prenatal ultrasound, follow up testing such as an amniocentesis or chorionic villus sampling may be ordered to further investigate a diagnosis.

Last updated on 05-01-20

Is cat eye syndrome inherited?

Most cases of cat eye syndrome are not inherited. The condition generally occurs sporadically as a random event during the formation of the egg or sperm. In this case, a person would have no family history of the condition but could pass it on to children.

Rarely, cat eye syndrome is passed down from parent to child. Some of these cases are the result of a balanced translocation in one of the parents. Carriers of a balanced translocation generally do not have any unusual symptoms or health problems; however, they have an increased risk of having children with a chromosome abnormality. In other cases, the parent may have a small extra (duplicate) chromosome made up of genetic material from chromosome 22 in some (mosaicism) or all of their cells. Because the symptoms and severity can vary between family members, the parent may not have any obvious symptoms or may only be mildly affected.

Last updated on 05-01-20

What is the long-term outlook for people with cat eye syndrome?

The long-term outlook (prognosis) for people with cat eye syndrome varies from person to person and largely depends on the severity of the condition and the associated signs and symptoms, specially when there are heart or kidney problems. Some babies who are very severely affected die during infancy; however, most people with cat eye syndrome do not have a shortened life expectancy.

Last updated on 05-01-20

How common is cat eye syndrome?

Around 1 out of 50,000 to one of out 150,000 people in the general population are thought to have cat eye syndrome.

Last updated on 05-01-20

How might cat eye syndrome be treated?

Because cat eye syndrome affects many different systems of the body, medical management is often provided by a team of doctors and other healthcare professionals. Treatment for this condition varies based on the signs and symptoms present in each person. For example, congenital heart defects; anal atresia; cleft lip and/or palate; and certain skeletal abnormalities may require surgery. Children with delayed motor milestones (i.e. walking) may be referred for physical therapy or occupational therapy. Special education services are often necessary for children with intellectual disability.

Last updated on 05-01-20

Name: Chromosome 22 Central - US Office 7108 Partinwood Drive
Fuquay-Varina, NC, 27526 , United States
Phone: 919-567-8167 Email: Url:
Name: Unique – Rare Chromosome Disorder Support Group G1, The Stables Station Road West
Surrey RH8 9EE
United Kingdom
Phone: +44 (0)1883 723356 Email: Url:
Name: March of Dimes 1275 Mamaroneck Avenue
White Plains, NY, 10605, United States
Phone: 914-997-4488 Toll Free: 888-663-4637 Fax : 914-997-4763 Email: Url:
Name: Cat Eye Syndrome International via Casape 26
Rome, 00156, Italy
Phone: +39- 6 -95 06 05 03 Email: Url:
Chromosome 22 Genetics Home Reference (GHR). 2016; Reference Link Cat Eye syndrome clinical synopsis Online Mendelian Inheritance in Man. October 22, 2013; Reference Link

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The RareGuru disease database is regularly updated using data generously provided by GARD, the United States Genetic and Rare Disease Information Center.

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