Definitions of Cat Eye Syndrome

Cat Eye Syndrome

Cat ‘s eye syndrome is a rare hereditary disease. Among other things, this causes changes in the eyes.

What is Cat’s Eye Syndrome?

Cat’s eye syndrome is inherited in an autosomal dominant manner and is congenital. The disease is caused by an abnormality in chromosome 22.

In medicine, cat’s eye syndrome is also known as coloboma-anal atresia syndrome or Schmid-Fraccaro syndrome. This hereditary disease involves changes in the eyes (coloboma) and malformations in the rectum (anal atresia). See AbbreviationFinder for abbreviations related to Cat Eye Syndrome.

The term cat’s eye syndrome can be traced back to the typical pattern of the disease. For example, there are vertical-oval cleft formations on the iris of the eye that are already innate. The eyes of the sick therefore have a cat-like appearance. The description of a syndrome consisting of anal atresia and an iris coloboma was made in 1878 by the Swiss ophthalmologist Otto Haab (1850-1931).

This led to the designation coloboma-anal atresia syndrome. The cat’s eye syndrome has only been considered an independent disease since 1969. Since 1965, the existence of an extra chromosome has been known. The Swiss geneticist Werner Schmid (1930-2002) and the Italian scientist Marco Fraccaro (1926-2008) played a significant role in this discovery. The term Schmid-Fraccaro syndrome is due to them.

In 1972, Erica Bühler realized that the extrachromosome originated from chromosome 22. This made it clear that a partial trisomy 22 was present. Cat eye syndrome is very rare. The frequency of the hereditary disease per 100,000 people is 1.35 cases. A total of about 105 cases are known.


Cat’s eye syndrome is inherited in an autosomal dominant manner and is congenital. The reason for the disease is an anomaly of chromosome 22. In around 83 percent of all patients, a small excess extrachromosome forms in all body cells. This extra chromosome contains part of the genetic information of chromosome 22.

Some physicians suspect that the extra chromosome comes about through an inversion duplication. For this reason it is bicentric and has satellites at its two ends. In the affected areas, the genetic information is more than duplicated in the genome of the affected person. Therefore, doctors also refer to cat’s eye syndrome as trisomy or tetrasomy. However, not every patient has an extra chromosome. In these cases, a gene mutation or unrecognized translocations are suspected as causes.

Symptoms, Ailments & Signs

The genetic symptoms of cat eye syndrome vary from person to person. Thus, the congenital vertical-oval cleft formations on the iris do not automatically occur in every patient. A combination of the key symptoms occurs in only about 40 percent of all patients.

Typical symptoms of the cat’s eye syndrome are anal atresia, in which the perforation of the anal fossa in the direction of the rectum does not occur, and other anorectal malformations. In addition, unilateral or bilateral iris colobomas and preauricular appendages form. This means lobule-like appendages immediately in front of the auricle. They consist of skin or connective tissue.

Another feature of the hereditary disease is an oblique axis of the eyelid in the outer and lower direction. In many cases, there is also a mental handicap. Some patients also develop malformations in the urinary and genital apparatus. This can be a misaligned orifice of the urethra, a sac kidney or double ureters.

The skeletal system of the patient is also sometimes affected, which is noticeable in the form of missing thumbs, short stature, spina bifida (neural tube malformation), mermaid syndrome (sirenomelia) or deformed ribs. In addition, the eyes show various symptoms such as a Mongolian line, squinting, a large distance between the eyes, pathological reduction of the size of the eyeball, retinal dysplasia and cataracts.

In some cases, cardiac abnormalities such as an isolated atrial -ventricular septal effect or tetralogy of Fallot are possible. Furthermore, the bile duct system can be affected by gallbladder atresia, the large intestine by Hirschsprung disease and the brain by oligophrenia.

Diagnosis & course of disease

A diagnosis of the cat’s eye syndrome can usually be made by the characteristic key symptoms such as the iris coloboma and anal atresia, without the need for a genetic analysis. In addition, a chromosome analysis is within the realm of possibility. The most reliable criterion for the diagnosis of cat’s eye syndrome is the detection of the extra chromosome.

The diagnosis can also be made in patients in whom there are no detectable changes in the genetic make-up, but who do have typical symptoms. Abnormal hand and foot positions or unusually long thumbs are then considered important clues.

The course of cat’s eye syndrome depends on the severity of the hereditary disease and the extent to which the kidney, heart and rectum abnormalities can be corrected. The level of psychomotor development also plays a decisive role. If there are only mild symptoms, there is no reduction in life expectancy.


The cat’s eye syndrome primarily causes various symptoms that appear in the patient’s eyes. Those affected suffer from changes in the iris. This can also lead to various malformations in the rectum, so that in the worst case there can be a complete breakthrough.

Most patients continue to suffer from an intellectual disability and are no longer able to carry out various everyday activities. They are mostly dependent on the help of other people. The urinary tract or the genitals can also be affected by malformations. The quality of life of the patient is honestly restricted and reduced by the cat’s eye syndrome.

Furthermore, those affected suffer from squinting and later in life from cataracts. Short stature also occurs in most patients. A heart defect can reduce life expectancy. Cat’s eye syndrome can only be treated symptomatically.

Many complaints can be corrected or limited, although this does not result in a completely positive course of the disease. In many cases, psychological treatment of the patients and their relatives or parents is also necessary.

When should you go to the doctor?

People who notice an optical change in their eyes should consult a doctor to clarify the cause. Clefting of the eye is considered unusual and is a sign of the presence of a genetic disorder. The first irregularities can already be detected after birth. Since newborns are examined intensively by obstetricians and paediatricians immediately after delivery, the irregularities are often already noticeable in this phase of life.

If a home birth takes place without the presence of a midwife, a doctor must be consulted immediately after the birth for a general examination of the health of the child. Alternatively, the visual changes can be seen as the child grows and develops and should be promptly examined by a doctor. Since the cat’s eye syndrome also leads to a malformation of the rectum, a doctor’s visit is necessary in the event of persistent digestive disorders.

If developmental problems in the child are noticed, the observations should also be discussed with a doctor. If the child shows reduced mental performance, a learning disability or impaired memory in direct comparison to peers, a doctor’s visit is necessary. If peculiarities of the skeletal system occur, a doctor must be consulted to clarify the cause. Short stature, deformities of the skeleton or disturbances in the natural range of motion must be examined by a doctor.

Treatment & Therapy

Surgical interventions are performed to treat the cat’s eye syndrome in order to correct the achievable deformities as much as possible. These include malformations of the anus and kidneys as well as congenital heart defects. Above all, the surgical correction of anal atresia is extremely important, because otherwise this will result in the early death of the child.

If the malformations cannot be corrected, this circumstance has a significant impact on the life expectancy of the patient. In addition, physiotherapy and curative education measures can be carried out. Consistent early support for the child and detailed advice for the parents concerned are also important. Other treatment options are still in the research phase.

Outlook & Forecast

For many of those affected, everyday life means that they are often dependent on the support of their family. Fortunately, there are ways to improve everyday life and thus the quality of life in the long term.

First and foremost here are early surgical corrections of any existing malformations in the area of ​​the urogenital tract and the anus. Regular visits to the specialist provide optimal support. Therapeutic massages and physiotherapy can be used for psychomotor development, some of which can also be deepened by relatives at home.

Frequent visits to the ophthalmologist enable early detection of a possible deterioration in vision and the prescription of appropriate therapy. If this requires a surgical intervention, the patient must pay attention to a few points in the aftercare. In the first few weeks, all direct sunlight must be avoided, as well as potentially irritating face creams or other care products. Good hand hygiene also reduces the risk of germs being transferred to the eyes. If an inflammatory reaction does occur, the doctor must be informed immediately.

Since scars remain after every surgical procedure, it is not uncommon for psychological suffering to follow. However, early psychotherapy usually brings rapid success. Contact with other affected people can also help both relatives and the patient themselves through the exchange of experiences.


Cat’s eye syndrome is one of the congenital hereditary diseases. For this reason, no effective prevention is possible. Family counseling, which takes place after a chromosome analysis, is considered sensible.


In most cases, those affected by cat’s eye syndrome have very few or even no special options for aftercare. They are primarily dependent on a quick diagnosis and subsequent treatment so that no further complications or symptoms occur. A doctor should therefore be contacted as soon as the first signs or symptoms of cat eye syndrome appear, so that the symptoms cannot worsen.

Cat’s eye syndrome cannot heal itself. Since this is a hereditary disease, it cannot be completely cured. In the case of a desire to have children, a genetic examination and counseling should always be carried out first in order to prevent the disease from reoccurring. The various malformations are alleviated by surgical interventions.

After the procedures, those affected should definitely rest and protect their bodies. Strenuous or physical activities should be avoided so that the body is not unnecessarily stressed. Those affected by cat’s eye syndrome are also dependent on the help and care of their parents and relatives. Contact with other patients with the syndrome can also be very useful, as this can lead to an exchange of information.

You can do that yourself

People who suffer from cat eye syndrome often depend on the support of family and friends. Some measures make everyday life easier for those affected and also improve quality of life and well-being in the long term.

First of all, comprehensive medical treatment is indicated for cat eye syndrome. Patients must visit the ophthalmologist regularly and inform them of any unusual symptoms. In this way, the therapy can be promptly adapted to any deterioration in vision and new complaints. Many problems can be treated surgically. Since eye surgery is always a complicated procedure, it is essential for the patient to comply with the doctor’s instructions regarding preoperative measures. The doctor must be informed in good time about the intake of medication, any allergies and other factors, if this has not already been done.

Rest and bed rest apply after the operation. The eyes must not be exposed to any major stress for a few days or weeks after the procedure. Direct sunlight and contact with potentially irritating care products should be avoided. If the affected eye becomes inflamed, the responsible doctor must be informed immediately. Even if the course is positive, there are often external abnormalities that should be discussed with a therapist. In this way, the occurrence of any psychological problems can be prevented.

Cat Eye Syndrome