A rare autosomal dominant disorder caused by an inverted duplicated 22, and characterized mainly by ocular iris coloboma, preauricular pits, heart defects, micrognathia, cleft palate, anal atresia, hernias, and kidney problems
In humans, the cat eye syndrome is a genetic disorder caused mainly by an inverted duplicated chromosome 22. The human chromosome 22 is a small autosome that contains about 400 to 500 genes. The cat eye syndrome is one of the disorders associated with pathological mutations of certain genes located in chromosome 22. It is mainly caused by an inverted duplicated portion of the chromosome 22. A small extra chromosome is duplicated. In particular, there is an extra genetic material represented by the duplication of the short arm (p) and a section of the long arm (q) of chromosome 22. Thus, instead of the typical two copies, there are three copies (trisomic) or even four copies (tetrasomic) of the chromosome 22. This accounts for the manifestation of symptoms characteristic of the cat eye syndrome. As the name implies, the individual with this condition has an ocular iris coloboma. It is when there is a gap in the iris of the eye. Other symptoms are small preauricular pits, heart defects, micrognathia, cleft palate, anal atresia, hernias, and kidney problems (e.g. underdeveloped kidneys). It can be passed on to offspring in an autosomal dominant mode of inheritance.