Costello Syndrome with Congenital Pulmonary Valve Stenosis and Ventriculomegaly—A Case Report

Costello syndrome is an extremely rare genetic disorder with growth delay after birth and typically results in short stature during childhood. It is one of the RASopathy of Ras/MAPK pathway syndromes. It affects the transforming protein p21, an enzyme that in humans is encoded by the HRAS gene. H-Ras is a small G protein and once bound to Guanosine triphosphate, it will activate a Raf kinase like C-Raf, the next step in the MAPK/ERK pathway (mitogen-actvated protein kinase/ extracellular signal-regulated kinase) i.e., MEK (mitogen-actvated ERK kinase), a protein that phosphorylate ERK which can directly and indirectly activate many transcription factors. This pathway is also known as Ras-Raf, MEK-ERK pathway, which is a chain of proteins on the cell that communicate a signal from a receptor on the surface of the cell to the DNA in the nucleus of the cell. Activation of ERK 1/2 is involved in signal transduction pathways associated with cardiac hypertrophy. The developmental syndromes caused by germline mutations in genes that alter the RAS components of the MAP/ERK signal transduction pathway are called “RASopathies”. Cardiovascular abnormalities are important features of Costello syndrome and other RASopathies such as Noonan syndrome. Background of this case report described the congenital valvular pulmonic stenosis and ventriculomegaly associated with Costello syndrome by transthoracic echocardiographic imaging in a 9-year-old male boy.