Cat Eye Syndrome (CES), also known as Schmid-Fraccaro Syndrome, is a rare genetic disorder characterized by specific physical and developmental abnormalities. It is named after the characteristic appearance of the eyes, which resembles a cat’s eye due to a particular eye anomaly. In this article, we explore the causes, symptoms, and genetic features associated with Cat Eye Syndrome.
Causes: Cat Eye Syndrome is caused by an abnormality in the structure of chromosomes, specifically chromosome 22. The majority of cases occur sporadically, meaning they are not inherited from parents but arise as a result of a random genetic event during early development. However, CES can also be inherited in some cases, following an autosomal dominant pattern.
The underlying genetic abnormality in CES is known as a supernumerary bisatellited marker chromosome, which is an additional small chromosome composed of duplicated genetic material from chromosome 22. This abnormal chromosome is present in cells throughout the body and can lead to the characteristic features of Cat Eye Syndrome.
Symptoms: Cat Eye Syndrome is associated with a wide range of symptoms that can vary in severity among affected individuals. Some of the most common symptoms and physical features include:
- Cat Eye Appearance: The hallmark feature of CES is the presence of coloboma, a defect in the iris of the eye that gives it a vertically elongated appearance resembling a cat’s eye. This feature is present in approximately 80% of individuals with Cat Eye Syndrome.
- Facial Abnormalities: CES can cause various facial abnormalities, including a short nose with a broad nasal bridge, downward slanting of the eyes (antimongoloid palpebral fissures), a small jaw (micrognathia), and low-set ears.
- Cardiac Defects: Many individuals with CES have congenital heart defects, such as ventricular septal defects (holes in the heart’s walls), atrial septal defects (abnormal openings between the heart’s upper chambers), or other structural abnormalities of the heart.
- Renal Anomalies: Kidney abnormalities, such as horseshoe kidney (fusion of the lower ends of the kidneys), hydronephrosis (enlargement of the kidneys due to urinary obstruction), or renal agenesis (absence of one or both kidneys), can occur in CES.
- Growth and Developmental Delays: Children with Cat Eye Syndrome may experience growth delays, both prenatally and after birth. Developmental delays in motor skills, speech, and cognitive abilities are also common.
Genetic Features: The characteristic genetic abnormality in Cat Eye Syndrome involves the presence of an extra, duplicated portion of chromosome 22. This additional genetic material can vary in size and composition, leading to variations in the severity and specific features of the syndrome among affected individuals.
Genetic testing, such as chromosomal analysis or fluorescence in situ hybridization (FISH), can detect the presence of the supernumerary bisatellited marker chromosome and confirm the diagnosis of Cat Eye Syndrome.
It is important to note that CES can exhibit significant variation in its presentation and associated features. Some individuals may have mild symptoms and a relatively normal lifespan, while others may experience more severe medical complications.
In conclusion, Cat Eye Syndrome is a rare genetic disorder characterized by physical abnormalities, including the distinctive appearance of the eyes. It is caused by an abnormality in chromosome 22, resulting in the presence of an extra, duplicated portion of genetic material. The symptoms and severity of Cat Eye Syndrome can vary among individuals. A comprehensive evaluation by healthcare professionals and genetic testing are crucial for accurate diagnosis and appropriate management of the condition.
