Cat-eye syndrome

Cat-eye syndrome (CES), also known as Schmid-Fraccaro syndrome or coloboma of iris-anal atresia syndrome, is a rare chromosomal disorder caused by the presence of a supernumerary bisatellited marker chromosome derived from chromosome 22. This marker chromosome typically consists of an inverted duplication of the region 22pter→22q11.2, resulting in partial tetrasomy of chromosome 22. The syndrome is named after the characteristic ocular coloboma (a gap or cleft in the iris) that gives the eye a cat-like appearance, although this feature is not present in all affected individuals. Cat-eye syndrome affects multiple body systems with highly variable expressivity, even among members of the same family. The classic triad of features includes ocular coloboma (iris and/or choroidal), anal atresia or stenosis (imperforate anus), and preauricular skin tags or pits. Additional features may include congenital heart defects (such as total anomalous pulmonary venous return and other cardiac malformations), renal anomalies (unilateral renal agenesis, hydronephrosis), skeletal abnormalities, and mild to moderate intellectual disability, though some individuals have normal intelligence. Craniofacial features can include downslanting palpebral fissures, micrognathia, and cleft palate. Short stature and biliary atresia have also been reported in some cases. There is no cure for cat-eye syndrome, and management is directed toward the specific symptoms present in each individual. Surgical correction may be required for anal atresia, congenital heart defects, and other structural anomalies. Regular ophthalmologic, cardiac, and renal monitoring is recommended. Early developmental intervention and educational support can benefit individuals with cognitive delays. Genetic counseling is important for affected families, as the supernumerary marker chromosome can be inherited from a mildly affected or phenotypically normal parent who carries the marker in some or all of their cells.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Cat-eye syndrome