Cat’s eye syndrome is the name given to a rare hereditary disease. Among other things, it causes changes in the eyes.
What is cat eye syndrome?
In medicine, cat’s eye syndrome is also known as coloboma anal atresia syndrome or Schmid-Fraccaro syndrome. In this hereditary disease, eye changes (coloboma) and malformations of the rectum (anal atresia) are present. The name cat’s eye syndrome can be traced back to the typical pattern of the disease. There are vertical-oval clefts in the iris of the eye, which are already congenital. The eyes of the patients therefore have a cat-like appearance. The description of a syndrome consisting of anal atresia and iris coloboma took place already in 1878 by the Swiss ophthalmologist Otto Haab (1850-1931). This led to the name coloboma anal atresia syndrome. However, the cat’s eye syndrome has been considered as an independent disease only since 1969, when the existence of an extra chromosome was already known. The Swiss geneticist Werner Schmid (1930-2002) and the Italian scientist Marco Fraccaro (1926-2008) played an important role in this discovery. The name Schmid-Fraccaro syndrome can be traced back to them. In 1972, Erica Bühler discovered that the origin of the extra chromosome was chromosome 22, which made it clear that partial trisomy 22 was present. Cat’s 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.
Causes
Cat’s eye syndrome is inherited in an autosomal dominant manner and is already congenital. The reason for the disease is an abnormality of chromosome 22. In about 83 percent of all sufferers, a small excess extra chromosome forms in all body cells. This extra chromosome contains part of the genetic information of chromosome 22. Some physicians suspect that the extra chromosome is the result of an inversion duplication. For this reason, it is bicentric and has satellites at its two ends. In the affected areas, the genetic information is present more than twice in the genome of the affected individuals. Therefore, doctors also refer to the cat’s eye syndrome as trisomy or tetrasomy. However, an extra chromosome is not detectable in every patient. In these cases, a gene mutation or unrecognized translocations are suspected causes.
Symptoms, complaints, and signs
The genetic symptoms of cat’s eye syndrome vary from person to person. Thus, not every patient automatically develops the congenital vertical-oval clefts on the iris. A combination of the leading symptoms occurs only in about 40 percent of all patients. Typical symptoms of cat’s eye syndrome are anal atresia, in which the anorectal fossa fails to erupt in the direction of the rectum, and other anorectal malformations. In addition, unilateral or bilateral iris colobomas and preauricular appendages form. This refers to lobule-like appendages immediately in front of the auricle. They consist of skin or connective tissue. Another feature of the hereditary disease is an eyelid axis that runs obliquely in the outer and lower directions. In many cases, mental retardation is also present. Some patients also have malformations of the urinary and genital apparatus. These may include a displaced orifice of the urethra, a water sac kidney, or double ureters. The skeletal system of the affected person is also sometimes affected, which becomes apparent through missing thumbs, short stature, spina bifida (neural tube malformation), a mermaid syndrome (sirenomelia) or deformed ribs. In addition, the eyes show various symptoms such as a mongolian fold, strabismus, a large distance between the eyes, pathological reduction of the eyeball, retinal dysplasia, and cataract. In some cases, cardiac defects such as isolated septal atrium and ventricle or tetralogy of Fallot are possible. Furthermore, the biliary system may be affected by gallbladder atresia, the colon by Hirschsprung’s disease, and the brain by oligophrenia.
Diagnosis and course of the disease
A diagnosis of cat’s eye syndrome can usually be made already by the characteristic leading symptoms such as iris coloboma and anal atresia, without the need for genetic analysis. In addition, chromosomal 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 material, but in whom there are typical symptoms. Abnormal hand and foot positions or unusually long thumbs are then considered important clues. The course of the cat’s eye syndrome depends on the severity of the hereditary disease and the extent to which the malformations of the kidneys, heart and rectum can be corrected. The level of psychomotor development also plays a decisive role. If only mild symptoms are evident, there is no restriction of life expectancy.
Complications
Due to cat’s eye syndrome, various complaints primarily occur in the patient’s eyes. In this case, the affected person suffers from changes in the iris. Thereby it can come likewise to different malformations at the rectum, so that it can come in the worst case also to a complete break-through. Most patients also suffer from mental retardation and are unable to perform various everyday tasks. They are mostly dependent on the help of other people. Also the urinary tract or the genitals can be affected by malformations. The quality of life of the patient is honestly limited and reduced by the cat’s eye syndrome. Furthermore, those affected suffer from strabismus and, later in life, cataracts. Most patients also suffer from short stature. Due to a heart defect, life expectancy may be reduced. Treatment of cat’s eye syndrome can only be symptomatic. Many symptoms can be corrected or limited, although there is no complete positive course of the disease. In many cases, psychological treatment of patients and their relatives or parents is also necessary.
When should you see a doctor?
People who notice a visual change in the eyes should consult a doctor to determine the cause. Clefting of the eye is considered unusual and is a sign of the presence of a genetic condition. The first irregularities may be noticed as early as after birth. Since newborns are intensively examined by obstetricians as well as pediatricians immediately after delivery, the irregularities are often noticed at this stage of life. If a home birth takes place without the presence of a midwife, a doctor should be consulted immediately after the birth for a general examination of the child’s health. Alternatively, the visual changes are evident in the child’s growth and development phase and should be examined by a physician immediately. Since cat’s eye syndrome also leads to malformation of the rectum, a visit to the doctor is necessary if digestive disorders persist. If developmental problems are noticed in the child, the observations should also be discussed with a physician. If the child shows reduced mental performance, learning disabilities or disturbances in memory skills in direct comparison with peers, a visit to the doctor is necessary. If peculiarities of the skeletal system occur, a physician should be consulted to determine the cause. A short stature, deformations of the skeleton or disturbances of the natural movement possibilities must be examined by a doctor.
Treatment and therapy
To treat cat’s eye syndrome, surgical procedures are performed to correct the achievable malformations as much as possible. These include malformation of the anus and kidneys and congenital heart defects. Above all, surgical correction of anal atresia is extremely important, because otherwise it 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 sufferer. In addition, physiotherapeutic and curative measures can be taken. It is also important to provide consistent early support for the child and extensive counseling for the parents concerned.Other treatment options are currently still in the research phase.
Outlook and prognosis
For many affected individuals, everyday life means that they are often dependent on their family for support. Fortunately, there are ways to improve daily life and thus quality of life in the long term. Foremost among these are early surgical corrections of any existing malformations in the urogenital tract and anus. Regular visits to the specialist ensure optimal support. For psychomotor development, therapeutic massages and physiotherapy can be used, some of which can also be intensified by relatives in the home environment. Close visits to the ophthalmologist allow early detection of a possible deterioration of vision and the prescription of appropriate therapy. If this necessitates surgical intervention, the patient must observe a number of points during follow-up care. In the first weeks, any direct sunlight must be avoided, as well as possibly irritating face creams or other care products. Good hand hygiene also reduces the risk of germ transmission to the eyes. If an inflammatory reaction nevertheless occurs, the doctor must be informed immediately. As every surgical procedure leaves scars, it is not uncommon for psychological suffering to occur as a result. However, psychotherapy started at an early stage usually brings rapid success. Contact with other sufferers can also help, through the exchange of experiences, both relatives and the patient himself.
Prevention
Cat’s eye syndrome is one of the already congenital hereditary diseases. For this reason, no effective prevention is possible. Family counseling, which takes place after chromosomal analysis, is considered useful.
Follow-up
Affected individuals have very few or even no particular options for aftercare in most cases of cat’s eye syndrome. They are primarily dependent on a rapid diagnosis with subsequent treatment to prevent further complications or discomfort. Therefore, a doctor should be contacted at the very first sign or discomfort of cat eye syndrome to prevent further worsening of symptoms. There is no self-cure for cat eye syndrome. Since it is a hereditary disease, it cannot be completely cured. If a child is desired, genetic testing and counseling should always be done first to prevent the recurrence of the disease. The various malformations are alleviated by surgical interventions. After the interventions, affected persons should in any case rest and take care of their bodies. Strenuous or physical activities should be avoided so that the body is not unnecessarily stressed. Similarly, due to the cat’s eye syndrome, affected persons are dependent on the help and care of their parents and relatives. In this context, contact with other patients of the syndrome can also be very useful, as it can lead to an exchange of information.
This is what you can do yourself
Individuals suffering from cat’s eye syndrome often rely on the support of family members 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 their ophthalmologist regularly and inform him or her of any unusual symptoms. This allows therapy to be promptly adjusted to any worsening of vision and new symptoms that arise. Many problems can be treated surgically. Since eye surgery is always a complicated procedure, it is imperative that the patient follow the doctor’s instructions regarding preoperative measures. The physician must be informed at an early stage about the intake of medication, possible allergies and other factors, if this has not already been done. After surgery, rest and bed rest apply. The eyes must not be exposed to any major stress for a few days to weeks after the operation. Direct sunlight and contact with possibly irritating care products should be avoided. If the affected eye becomes inflamed, the responsible physician must be informed immediately.Even with a positive course, external abnormalities often remain, which should be discussed with a therapist. In this way, the occurrence of possible psychological problems can be prevented.
