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Genetic and Rare Diseases Information Center (GARD)

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Cat Eye syndrome

Other Names for this Disease
  • CES
  • Chromosome 22 partial tetrasomy
  • INV DUP(22)(Q11)
  • Schmid-Fraccaro syndrome
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What is Cat Eye syndrome?

What causes cat eye syndrome?

What is Cat Eye syndrome?

Cat Eye syndrome is a rare condition with widely variable features including structural defects of the iris of the eye (coloboma), skin tags near the ear, narrowing or closure of the anus (atresia), defects of the heart or kidneys, and intellectual disability.  It occurs when an individual inherits extra genetic material from chromosome 22, known as a marker chromosome, from a parent.  The marker chromosome generally arises by chance in the parent, though inheritance from an affected parent directly to a child has been observed.  The diagnosis of Cat Eye syndrome depends on finding a marker chromosome by genetic testing.[1]
Last updated: 2/28/2011

What causes cat eye syndrome?

Cat eye syndrome is most often caused by a chromosomal change called an inverted duplicated 22. In people with this condition, each cell has at least one small extra chromosome made up of genetic material from chromosome 22 that has been abnormally copied (duplicated). The extra genetic material causes the characteristic signs and symptoms of cat eye syndrome, including an eye abnormality called an iris coloboma (a gap or split in the colored part of the eye), small skin tags or pits in front of the ear, unusually formed ears, heart defects, kidney problems, malformations of the anus, and, in some cases, delayed development.[2]
Last updated: 12/5/2013

  1. Cat Eye Syndrome. OMIM. 2009; Accessed 2/27/2010.
  2. Chromosome 22. Genetics Home Reference (GHR). May 2012; Accessed 12/5/2013.