There are various congenital pathologies in children. Some of them are considered quite common. But there are rare diseases. Their prevalence is small. However, many have quite serious consequences. One of these pathologies is Noonan syndrome. Next, consider it in more detail. The article will describe how Noonan syndrome appears and why it appears. A photo of the disease will also be presented in the text.
General information
Noonan syndrome is a hereditary pathology. A mutated PTPN11 gene is passed on to offspring from its parents. As a rule, men are infertile. Therefore, the gene is transmitted through the maternal line. The familial nature of this disease is usually noted. Rare cases not related to heredity, however, they are also recorded in practice.
History reference
Practicing as a cardiologist-pediatrician, Jacqueline Noonan, working in the clinic of the University of Iowa, noticed that a certain group of children, which consisted of both boys and girls who had pulmonary artery stenosis, often had a short stature, eyes wide apart, a webbed neck located low auricles and ptosis. Having examined the combination of manifestations of heart disease with other developmental abnormalities in 833 patients, the doctor wrote an article in 1962. In her work, she described nine cases in which characteristic facial features, chest deformities, and stunting were noted against a congenital heart defect. The disease was found in both male and female persons.
Noonan syndrome: symptoms
There are a number of characteristic features that distinguish pathology from others. These include, but are not limited to:
- Short stature. In women - 1.53, in men - 1.63 m. At the time of birth, both body length and baby weight are within normal limits. Growth retardation begins at the age of 2-3 years.
- Face changes. Patients diagnosed with Noonan syndrome have almond-shaped eyes wide apart. In the inner corner there is a skin fold. Ptosis (eyelids down) is also noted due to weakened muscle function or due to small orbits. About two thirds of all children with pathology have visual impairment. With ptosis, the visual field is limited and strabismus develops.
- Violations of the structure of the jaws. Upper underdeveloped, arched high sky is observed. The position of the teeth on both jaws is incorrect.
- Low landing or deformation of the auricles. As a result of this anomaly, hearing is impaired.
- Short and wide neck.
- Thyroid chest with widely spaced nipples.
- Deformation in the elbow joint (congenital).
- Flat feet.
- Short fingers.
Malformations of internal organs
Noonan syndrome is most often accompanied by disorders in the activity of the cardiovascular system. Against the background of pathology, narrowing (stenosis) in the pulmonary trunk, as well as a defect in the interventricular septum, is detected. The second place is occupied by anomalies of the genitourinary system. So, from the side of the kidneys, defects such as hypoplasia (tissue development failure) or the absence of one kidney are detected. As for puberty, it varies from normal to completely defective. In girls, a late onset of menstruation is often noted, in boys - cryptorchidism or testicles are completely absent. Disorders of spermatogenesis are also detected. In some cases, sperm are completely absent. Against the background of operations with Noonan syndrome, increased bleeding is noted. Some patients may also show mild mental retardation .
Forms
There are two types of pathology:
- Family uniform. It is distinguished by the hereditary nature of the autosomal dominant type. In carriers of the mutant gene, the offspring appears with a pathology.
- Sporadic form. In this case, the mutation appears from case to case. However, the hereditary factor has not been identified.
Causes
The most common factor provoking pathology is the PTPN11 gene mutation. This cause is detected in 50% of patients. However, 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 may be triggered by a new mutation. It follows that parents with this gene have no great chance of having another child.
Diagnosis
It is set in accordance with characteristic external features (they are described above). Also, during diagnosis, laboratory indicators are examined. In particular, there is a decrease in the concentration of testosterone, XII coagulation factor. Instrumental studies are also being conducted. An x-ray of the sternum, echocardiography, ECG is prescribed. Using these methods, anomalies of the internal organs are detected. The doctor may also schedule a consultation with a medical geneticist.
Therapeutic measures
Due to the genetic condition of the syndrome, treatment is mainly aimed at eliminating the symptoms. With cryptorchidism, an operation is prescribed. During it, the testes move into the scrotum. Against the background of a decrease in the concentration of androgens, hormonal therapy is recommended. In the presence of renal failure, hemodialysis is prescribed. With its help, metabolic products are removed from the body through extrarenal blood purification.