Intelligence is not normally affected, but some people may have learning difficulties or mild intellectual disabilities. A number of other coagulation factors can be depressed, and low factor XII and factor VIII activity are the next most frequent depressions. A mouse model bearing the NS-causative Asp61Gly mutation in the Ptpn11 gene has been recently generated and characterized. There is an increased incidence of cognitive issues and learning disabilities, an increased incidence of brain abnormalities, and a wide array of other neurologic problems. Other important phenotypic features include reduced growth, bleeding disorders, and a variable degree of neurocognitive delay. This occurs in most people with Noonan syndrome, with or without abnormal heart structures. In a recent study a specific RAF1 mutation p.
The short stature in patients with Noonan syndrome can be treated with growth hormone which has been shown to improve final adult height. It impacts bone development and has a range of distinctive symptoms and characteristics. Treatments may include surgery. Less commonly, factor IX and factor II have also been reported to be deficient in patients with NS and can contribute to bleeding risk. There is also an increased incidence of serious cervical spine disorders, including cervical stenosis, Arnold-Chiari malformation, and syringomyelia. People with Noonan syndrome have distinctive facial features such as a deep groove in the area between the nose and mouth philtrum , widely spaced eyes that are usually pale blue or blue-green in color, and low-set ears that are rotated backward.
During cardiac catheterization, a small hollow tube catheter is inserted into a large vein and threaded through the blood vessels leading to the heart. Noonan syndrome must be considered in differential diagnosis with Turner syndrome karyotype analysis and with the others RAS opthaties. All references are available in the References tab. Some affected individuals have vision or hearing problems. According to genotype-phenotype analysis pulmonary stenosis is more prevalent among who have PTPN11 mutations than patients without these mutations, whereas hypertrophic cardiomyopathy is less prevalent among those with PTPN11 mutations. If the PVS is or becomes clinically significant, initial treatment is usually pulmonary balloon valvuloplasty, but it may be unsuccessful if the valve is dysplastic. American Journal of Medical Genetics A:
All the genes implicated in Noonan syndrome encode proteins integral to this pathway and disease-causing mutations usually enhance signal flow through this pathway. Prader-Willi syndrome can also be associated with delayed puberty. Testicular histology is variable and is reported to range from normal to complete absence of spermatogonia Sertoli cell only syndrome. Giordano, in Cardiovascular Pathology Fourth Edition , Noonan Syndrome Noonan syndrome is recognized as the second most common genetic syndrome associated with cardiac abnormalities, with an incidence of 1: A delayed pubertal growth spurt has been documented in both sexes, bone maturity is also usually delayed.