Noonan Syndrome: Description, signs, treatment

There are various congenital pathologies in children. Some of them are considered quite common. But there are rare diseases. Their prevalence is low. However, many have serious consequences. One of these pathologies is the Noonan syndrome. Let us consider it in more detail. The article will describe how the Noonan syndrome manifests itself and why. Photo of the disease will also be presented in the text.

General information

The Noonan syndrome is a hereditary pathology. The mutated PTPN11 gene from the parents carrying it is passed on to the offspring. As a rule, men are barren. Therefore, the gene is transmitted through the maternal line. Usually, the family character of this disease is noted. Rare cases not related to heredity, however they are also recorded in practice.

Historical reference

At one time, practicing as a pediatric cardiologist, Jacqueline Noonan, working at the University of Iowa clinic, noticed that a certain group of children, in which both boys and girls with pulmonary artery stenosis consisted, often had low stature, wide-eyed, membranous neck , Located low in the ear and ptosis. Having studied the combination of manifestations of heart disease with other developmental anomalies in 833 patients, the doctor wrote an article in 1962. In her work, she described nine cases in which the characteristic features of the face, chest deformities and short stature were noted against a congenital heart defect . The disease was found in both male and female.

Noonan Syndrome: symptoms

There are a number of characteristic features that distinguish pathology from others. These include, in particular:

• Low growth. At women - 1,53, at men - 1,63 m. At the moment of a birth both length of a body, and a weight of the child is within the limits of norm. The delay in growth begins at the age of 2-3 years.
• Change of face. Patients who have Noonan syndrome diagnosed have widely almond - shaped eyes . In the inner corner there is a skin fold. Also noted ptosis (lowered eyelids) due to a weakened muscle function or due to small eye sockets. Approximately two-thirds of all children with pathology have visual impairment. With ptosis, the field of vision is limited and strabismus develops.
• Disturbances in the structure of the jaws. The upper one is underdeveloped, there is an arched high sky. On both jaws the interposition of teeth is wrong.
• Low landing or deformation of the auricles. As a result of this anomaly, hearing was disturbed.
• Short and wide neck.
• Shchitobraznaya chest with widely spaced nipples.
• Deformity in the elbow joint (congenital).
• Flat feet.
• Short fingers.

Malformations of internal organs

Syndrome Noonan is most often accompanied by violations in the activity of the cardiovascular system. Against the background of pathology, narrowing (stenosis) in the pulmonary trunk is revealed, as well as a defect in the interventricular septum. The second place is occupied by abnormalities of the genitourinary system. So, from the kidneys are revealed such defects as hypoplasia (insufficiency of tissue development) or the absence of one kidney. As for puberty, it varies from normal to absolutely defective. Girls often have a later onset of menstruation, boys - cryptorchidism or testicles are completely absent. There are also violations of spermatogenesis. In a number of cases, spermatozoa are completely absent. Against the background of operations with Noonan syndrome, there is increased bleeding. In some patients, mental development abnormalities can also be detected in an easy degree.

Forms

There are two types of pathology:

• Family form. It is distinguished by the hereditary nature of the autosomal dominant type. In the carriers of the mutant gene, the offspring appear with pathology.
• Sporadic form. In this case, the mutation appears from case to case. In this hereditary factor is not identified.

Causes

The most common factor that provokes pathology is the mutation of the PTPN11 gene. This reason is revealed in 50% of patients. Nevertheless, in a certain percentage of people with this syndrome, the genetic factor is unclear. Inheritance of pathology occurs in an autosomal dominant form. The syndrome can be triggered by a new mutation. From this it follows that parents with such a gene are not likely to have another child.

Diagnosis

It is installed in accordance with the characteristic external features (they are described above). Also in the diagnosis of laboratory tests are investigated. In particular, there is a decrease in the concentration of testosterone, the XII factor of coagulation. Instrumental research is also conducted. An x-ray of the sternum, echocardiography, ECG is prescribed. With the help of these methods, anomalies of internal organs are revealed. The doctor can also prescribe a medical genetics consultation .

Therapeutic events

In connection with the genetic conditionality of the syndrome, the treatment is directed mainly to the elimination of symptoms. With cryptorchidism, surgery is prescribed. In the course of her testicles move into the scrotum. Against the background of a decrease in the concentration of androgens, hormone therapy is recommended. In the presence of renal failure, hemodialysis is prescribed. With its help, the removal of metabolic products from the body by means of extrarenal blood purification is carried out.