The estimated incidence is at ~1 in 1000-2500 . As individuals have normal number of chromosomes, both males and females can be affected.
An immense number of clinical features have been described which can be present at varying degrees. These include:
- generalized musculoskeletal
- short stature
- delayed sternal ossification
- renal anomalies
- dilated renal pelvices
The inheritance is autosomal dominant although a significant proportion of cases are sporadic. Many genes have been implicated, the most common being the PTPN11 gene which encodes for SHP2, which results in an inability to inactivate SHP2 causing increased signaling of the Ras/MAPK pathway. However. other genes that may be less commonly implicated including SOS1, KRAS, RAF1, NRAS, and SHOC2 . Because of its effect in amplifying the Ras/MAPK pathway, it is considered to be a RASopathy .
Early 1 trimester ultrasound may show nuchal edema or a cystic hygroma similar to that of Turner syndrome. With subsequent scanning, some of the above individual clinical features may be present sonographically.
History and etymology
It is named after Jacqueline A Noonan (1928-fl 2019), an American pediatric cardiologist .
- Pectus excavatum
- cystic hygroma
- Pectus carinatum
- Persistierender Ductus arteriosus
- pulmonary stenosis
- Hypertrophe Kardiomyopathie
- Kardio-fazio-kutanes Syndrom
- nuchal oedema
- low-set ears /
- Ebstein anomaly
- low set ears
- mandibuläre Retrognathie
- angeborene renale Anomalien
- Keratozystischer odontogener Tumor
- orbital hypertelorism
- fetal cardiomyopathy
- persistent right umbilical vein
- absent ductus venosus
- Juvenile myelomonozytäre Leukämie
- congenital pulmonary arterial stenosis
- keratocystic odentogenic tumour