Cat Eye Syndrome is the more common name for a condition involving a partial trisomy or tetrasomy of part of chromosome 22. A small extra chromosome (humans normally have only 2) made up of the top half of chromosome 22 – the “p” arm, as well as the portion of the long arm of chromosome 22 down to the breakpoint q11.2, is found to be present either three times (trisomy) or four times (tetrasomy ).
Cat Eye Syndrome is also known in the literature as Schmid-Fraccaro Syndrome, Partial Tetrasomy 22, or Inv Dup(22)(q11) (Inverted Duplication). It is often referred to as Cat Eye Syndrome as some of the people affected may have coloboma of the iris – which make their eyes appear to look like cat’s eyes. This feature however, is only reported in about half of the known cases. The earliest reports stem back over 100 years ago, but the first association
Clinically, this is one of the more variable syndromes. People who have Cat Eye Syndrome can be anywhere from normal to suffering from severe malformations. This has proven true of the people who have joined our group, who have this condition.
Some of the features seen in people with CES include coloboma of the iris, anal atresia, ear tags and/or ear pits, heart defects, and kidney malformations, but because of the variability, there have been reports of malformations affecting almost every organ.
Cognitively, people with CES can be considered either normal intelligence, or have varying degrees of mental delay, although it is rare to see severe mental impairment in this condition.
The condition usually arises spontaneously, but our group does have some members who have CES and have passed it on to their children.