Medical expert of the article
New publications
Noonan syndrome: causes, symptoms, diagnosis, treatment
Last reviewed: 04.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Noonan syndrome is named after the author who described this disease in 1963. It occurs with a frequency of 1 in 1000-2500 newborns.
What causes Noonan syndrome?
Noonan syndrome is a hereditary autosomal dominant disease. In 50% of cases, molecular genetic verification of PTPN11 gene mutations is possible.
Symptoms of Noonan Syndrome
Newborns have growth retardation (length at birth is 48 cm) with normal body weight. Congenital heart defects (valvular stenosis of the pulmonary artery, ventricular septal defect), cryptorchidism in boys in 60% of cases, combined deformation of the chest are diagnosed from birth. Various defects of blood clotting factors (up to 50%) and dysplasia of the lymphatic system are common. Mental retardation occurs in 1/3 of patients.
How to recognize Noonan syndrome?
Noonan syndrome is diagnosed based on the combination of short stature, broad or webbed neck, chest deformity, congenital heart defects, and an unusual facial phenotype (frontal bossing, hypertelorism, rotated ears with drooping whorls).
What tests are needed?
Treatment of Noonan syndrome
Surgical treatment
- Blood coagulation disorders are found in 20% of cases (factor XI deficiency, von Willebrand disease, platelet dysfunction).
- An increased incidence of congenital chylothorax and chylopericardium is noted.
- Hypoplasia or aplasia of the lymphatic vessels is detected in 20% of cases in the form of generalized or peripheral lymphostasis, lymphangiectasia of the lungs or intestinal wall; during cardiac surgery and damage to the thoracic lymphatic duct, chylopericardium or chylothorax develops.
- Malignant hyperthermia is possible during anesthesia, the probability is low (1-2%), but given the seriousness of this complication, caution is recommended during anesthesia. The use of dartrolene is indicated.
What is the prognosis for Noonan syndrome?
It is determined by the spectrum of identified congenital defects and the presence of mental retardation.
Использованная литература