What is Cat Eye Syndrome: Causes, Symptoms, Treatment, Diagnosis

Cat Eye Syndrome also known as Schmid-Fraccaro Syndrome is a very rare disease. It is a very serious chromosomal disease caused when chromosome 22 is present 3 or 4 times where originally it should be 2. It may affect many parts of the body like eyes, ears, heart, and kidneys. Cat Eye Syndrome affects the mentioned body parts even before they are formed. The disease is congenital, and hence, people are born with it. Individual’s affected with Cat eye syndrome has a cat-shaped eyes, hence the name. Only 1 in 50,000 people have this disease. Some people might not even notice that they have Cat Eye Syndrome because of mild symptoms ^[1]. Majority of people with the Cat Eye Syndrome live a normal life. Due to severe malformations, some patients might die during their early childhood.

The symptoms of Cat Eye Syndrome vary from person to person. The most common body parts which get affected during the Cat Eye Syndrome are eyes, kidneys, ears, heart, intestines, and reproductive organs.

Some common symptoms of cat eye syndrome are:

• Cleft lip
• The Crossing of the eye or one eye being abnormally smaller than the other
• Coloboma
• Defects in bones
• Hernia
• Abnormal facial features
• Downward slanting between the lower and upper eyelid
• A narrow anal opening(anal atresia)
• Abnormal kidneys
• Urinary tract defects
• Short stature
• Defects in reproductive organs and tract
• Absence of tissue from the colored part of the eye
• Heart defects
• Abnormally shaped ears which may lead to improper hearing ability.
• Very common symptoms of Cat Eye Syndrome, which are almost present in every patient, are small skin growth on the outer ear, depressed skin on the outer ears and anal atresia.
• Some children might also face delays in learning or speaking. Not all features are present in every patient of Cat Eye Syndrome.

There are 23 chromosomes present in the human body. Cat Eye syndrome occurs when there is an abnormality in the child’s chromosome 22. Each chromosome has a short arm, a long arm and the part where both the arms connect. Usually, 2 copies of chromosome 22 are present in the human body. In Cat Eye Syndrome, there are two extra copies present each of the short arm and a small part of the long arm of chromosome 22 ^[1]. This leads to the abnormal growth of body parts of the child in the embryonic stage. The exact cause is not yet understood.

The presence of the extra copies of the chromosome is not inherited but they are formed randomly while cell division. There is a high risk that Cat Eye Syndrome will be inherited from the parent to the child and a chance of it being transmitted to several generations exists.

Even before the baby is born, the doctor can detect the presence of Cat Eye Syndrome using Ultrasound technology. In ultrasound, an image of the fetus is generated using high-frequency sound waves. The defective body parts which are symptoms of the Cat Eye Syndrome are captured in this image. After this, the doctor might recommend you tests like an amniocentesis, in which the fluid from the womb is withdrawn and analyzed, or chorionic villus sampling, in which a small sample of the placenta is taken through abdomen or vagina and tested. During this test, the extra chromosomes, if present, are found.

Further, a specialist will perform two genetic tests on these samples-

1. Karyotype – A picture of chromosomes is given so as to observe any abnormalities.
2. Fluorescence in situ hybridization – fluorescent dye is used to highlight the chromosomes.

Thus, the doctor can detect the Cat Eye Syndrome even before the child’s birth. A bone biopsy can also reveal whether or not the child has the Cat Eye Syndrome. Once it is confirmed that the child has Cat Eye Syndrome, multiple tests will be performed to check for other body part abnormalities, like heart defects, abnormal kidneys, and so on, which are:

• Electrocardiography
• Eye tests
• X-rays
• Hearing tests
• Echocardiography
• Cognitive function tests.

Complications of Cat Eye Syndrome depend on the symptoms a patient is showing. However, the most common complications of Cat Eye Syndrome are:

• Vision defects caused by Coloboma
• Heart defects
• Problems in one or both kidneys and urinary tract
• Mental disorders
• Hearing problems.

Symptoms of Cat Eye Syndrome vary from person to person. Thus, the treatment varies from person to person, depending on their condition and symptoms. Cat Eye Syndrome has no cure as an overall disease as it is a permanent genetic change, but each individual problem can be looked upon. These individual treatments might prolong for life. The treatment will require the coordination and support of various specialists. The individual treatments include various medications, surgeries, therapies, and so on.
Coloboma can never be completely treated, but the eye-sight can be slightly improved using glasses. Heart defects can be treated in most of the cases with the help of surgeries. The extra skin accumulated near ears or eyes can also be removed using some minor surgeries. The surgery for anal atresia is performed soon after the birth of the child. Hyperactivity can be dealt with therapies and counseling. Minor surgery can be performed to treat Preauricular tags/pits. Pulmonary venous malformations are treated by covering the affected site by medical glue. Hormonal therapy is suggested for short stature. Speech therapy is suggested for problems with talking.

Cat Eye Syndrome is a rare chromosomal disease. It is detected even before the birth of the child. There are various body parts which get affected due to this disease. The life expectancy varies depending on the extent to which the syndrome has affected the patient. Depending on the severity of the malformations, the patient may live a normal life or may die at a very early age. Cat Eye Syndrome can never be cured completely. Hence, people must be made known to this disease and its treatments.

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