Which genetic variant is associated with Noonan Syndrome?

Noonan Syndrome is a genetic disorder characterized by a variety of distinctive features including short stature, congenital heart defects, and characteristic facial features. The most common genetic variant associated with Noonan Syndrome is found in the PTPN11 gene. PTPN11 encodes a protein that plays a critical role in the signaling pathways of cells, particularly in those involving growth and proliferation, which can lead to the characteristic features of Noonan Syndrome when mutated.

Mutations in the PTPN11 gene are responsible for approximately 50% of Noonan Syndrome cases, making it a key focus for genetic testing and diagnosis in individuals presenting with the clinical features of this condition. Other genes, such as HRAS, also have variants associated with Noonan Syndrome, but they are not as prevalent as those in PTPN11.

The other options listed, while important in their respective conditions, do not play a significant role in Noonan Syndrome specifically. For instance, MYH7 is primarily associated with cardiac conditions like hypertrophic cardiomyopathy, HPRT1 is linked to Lesch-Nyhan syndrome, and HRAS mutations can cause different syndromic presentations but are less common compared to those seen in PTPN11. Thus, the identification