Noonan syndrome is a rare genetic disorder that affects multiple parts of the body, including growth, facial features, the heart, and overall development. Although present from birth, its signs and severity can vary widely from person to person. Early diagnosis and proper medical management can significantly improve quality of life for individuals with Noonan syndrome.
What Is Noonan Syndrome? Noonan syndrome is an autosomal dominant genetic condition, meaning it can be inherited from one affected parent or occur due to a spontaneous genetic mutation. It belongs to a group of disorders known as RASopathies, which are caused by abnormalities in the RAS/MAPK signaling pathway responsible for cell growth and development.
The condition affects both males and females and occurs across all ethnic groups.
Causes and Genetic Basis Noonan syndrome is caused by mutations in genes involved in cell signaling. The most commonly affected genes include:
PTPN11 (most frequent cause)
SOS1
RAF1
KRAS
NRAS
RIT1
These genetic changes disrupt normal development, leading to the physical and medical features associated with the disorder.