Cat's eye syndrome

Chromosomal diseases are a large group of genetic hereditary pathologies, including cat eye syndrome (synonyms: CES, duplication of 22 chromosomes (22pt-22q11), partial tetrasomy of 22 chromosomes (22pter-22q11), partial trisomy 22 chromosomes (22pter-22q11) , Schmid-Frakkaro syndrome). This syndrome is a relatively rare chromosomal disease, which is characterized by two main symptoms: atresia (absence) of the anus and an anomaly in the development of the iris that looks like a cat's eye.

[1], [2], [3], [4], [5], [6], [7]

Epidemiology

The prevalence of this pathology is 1 case per 1,000,000 newborns.

[8]

Causes of the cat's eye syndrome

The fundamental role in the development of the disease is assigned to the hereditary factor: in the presence of a sick person with cat eye syndrome in the family, the probability of having a child with a similar pathology is great.

[9]

Pathogenesis

The pathogenesis and type of inheritance of the disease is still unknown, since the pathology is sporadic. In some cases, we identified experts redistribution of the microstructure of chromosome 22 (trisomy incomplete as a result interstitial duplication 22q11.2), and a small additional acrocentric chromosomes that occurs suddenly due to a failure in the step of cell division during gametogenesis mother or father.

Theoretically, it is assumed that pathology can be considered hereditary. Based on this theory, the mother or father has genetically different cells, that is, not all cells contain the same chromosomes. Since the acrocentric chromosome is not found in all cells, cat eye syndrome in this generation may not manifest itself, or be found in mild form.

[10], [11], [12], [13], [14]

Symptoms of the cat's eye syndrome

The cat's eye syndrome in medical circles is sometimes called partial tetrasomy of the 22 chromosomes, or Schmid-Frakkaro syndrome. The first signs are noticeable even at the time of the birth of the child and are characterized by the following symptoms:

• absence of anus, non-admission of testicles (cryptorchidism), underdevelopment or absence of uterus, umbilical or inguinal hernia, Hirschsprung disease, megacolon;
• absence of an iris portion of the eye from one or both sides;
• omission of the outer corners of the eye cracks, uneven eyes, epicanth, ocular hypertelorism, strabismus, unilateral microphthalmia, absence of the iris (aniridia), coloboma, cataract;
• protrusions or cavities at the anterior surface of the auricles, absence (atresia) of the external auditory canal, conductive hearing loss;
• heart valve apparatus defects (tetralogy of Fallot, defect of interventricular septum, pulmonary artery stenosis, right ventricular hypertrophy);
• defects in the development of the urinary system, renal failure, unilateral or bilateral renal hypoplasia and / or agenesis, hydronephrosis, cystic dysplasia;
• small growth;
• curvature of the spine, underdevelopment of the osseous system, scoliosis, abnormal fusion of some bones in the spine (vertebral fusions), radial aplasia, synostosis of certain ribs, hip dislocation, lack of some fingers;
• mental underdevelopment (not always, but in the vast majority of cases);
• underdevelopment of the lower jaw, cleft lip;
• propensity to hernia;
• discrepancy of the palate;
• other developmental shortcomings, such as vascular anomalies, semi-vertebra, etc.

Syndrome of the cat's eye at death

The cat's eye syndrome, as a hereditary disease, is often confused with the so-called effect, or the symptom of the "cat's pupil" - one of the first and obvious signs of the irreversible process of cell death - the biological death of a person. The essence of this effect is that with a slight pressure from both sides on the eyeball of the deceased pupil becomes oval (slightly elongated, like a cat). If the person is alive, the shape of the pupil does not change and remains round: this is due to the tone of the muscles holding the pupil, and also due to the persisting intraocular pressure.

After a person dies, the work of the central nervous system stops, the muscles relax, and blood pressure decreases due to the cessation of blood flow. As a result, the intraocular pressure drops sharply.

The symptom of the cat's pupil can be traced already after 10 minutes after the moment of biological death of the organism.

[15], [16]

Complications and consequences

The consequences of the syndrome depend on which congenital anomaly the born baby has. Important and the degree of defects, the performance of organs and systems, the timeliness of medical care.

How long the person with the cat's eye syndrome will live, no one can say. If you are engaged in a baby, maintain his health with medicines, adapt to the environment, then the disease prognosis can be called satisfactory. However, given that the syndrome is often accompanied by multiple developmental defects, the patient's quality and life expectancy can only be predicted after a thorough examination by specialists: a cardiologist, urologist, neurologist, surgeon, orthopedist, etc.

[17], [18], [19]

Diagnostics of the cat's eye syndrome

In most cases, the diagnosis is determined by the characteristic appearance of the child. For more accurate diagnosis, cytogenetic analysis and the study of the chromosome set of the baby can be prescribed. Such a study is recommended to be carried out even during the conception planning period, if members of the family already had cases of chromosomal abnormalities. If unsatisfactory results are additionally assigned:

• amniocentesis - analysis of amniotic (amniotic) waters;
• chorionic villus biopsy;
• cordocentesis - the analysis of umbilical cord blood.

As a rule, patients have an extra chromosome, which consists of a pair of identical sections of the 22 chromosomes. Such a site exists in the genome in four copies.

If the disease is provoked by doubling the site of 22q11, then in this case three copies are found.

[20], [21], [22]

Differential diagnosis

Differential diagnosis is performed with Rigger syndrome - mesodermal dysgenesis of the cornea and iris.

Treatment of the cat's eye syndrome

Children born with cat eye syndrome are subject to mandatory examination of narrow medical specialists. The treatment prescribed by them should be aimed at eliminating the symptoms and improving the quality of life of the child, as far as possible. This approach is due, first of all, to the fact that at present the given chromosomal disease is considered incurable.

First of all, surgical treatment may be needed to correct the digestive and cardiovascular system.

In addition, a course of medicines and psychotherapy can be prescribed to support psychomotor activity. LFK, regular massage sessions and manual therapy also have a positive effect on the child's condition.

As we already mentioned above, genetic testing of parents before the conception of a child is the best prevention of chromosomal abnormalities. If someone from family members or close relatives has been diagnosed with cat eye syndrome, future parents should carefully prepare for a possible pregnancy and exclude possible fetal anomalies in advance.