This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': "Cardiac abnormality seen with Noonan's syndrome is - \nSelect and explain. \nA. VSD, B. ASD, C. Pulmonary stenosis, D. Coarctation of aorta", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Noonan Syndrome :\n\nwere previously thought to have a form of Turner syndrome, with which Noonan syndrome shares a number of clinical features.\nThe observation that patients with Noonan syndrome have normal karyotypes was important in allowing the distinction to be made between the Turner and Noonan syndromes.\n\nPathophysiology :\n\nThe pathophysiology of Noonan syndrome is not fully understood. A disease-causing gene, PTPN11, has been identified. The gene product, SHP2, plays an important role in cardiac semilunar valve development.\n\nSex :\n\nNoonan syndrome occurs in either a sporadic or autosomal dominant fashion. In either case, males and females are affected equally.\n\nAge :\n\nThe disorder is present from birth, but age impacts upon the facial phenotype Infants with Noonan syndrome can be difficult to recognize by facial appearance alone. The phenotype becomes more striking in early childhood, but with advancing age, it may again become quite subtle. Careful examination of an affected child\'s parents may, in fact, reveal that they are affected mildly.\n\nClinical features -\nGrowth parameters\n\nSize at birth is usually within the reference range.\nShort stature is present in up to 80% of patients. Average adult height for males is 5\'55" and for females is 5\'.\n\nFacial features\n\nTriangular-shaped face\nHypertelorism\nDown-slanting eyes\nPtosis\nStrabismus\nAmblyopia\nRefractive errors\nLow-set ears with thickened helices\nHigh nasal bridge\nShort webbed neck\n\nChest/back features\n\nPectus carinatum/excavatum\nScoliosis\n\nCardiac features\n\nThe characteristic lesion is a dysplastic/stenotic pulmonic valve, but virtually all types of congenital heart defects have been described in patients with Noonan syndrome.\nHypertrophic cardiomyopathy (obstructive and nonobstructive types) is present in up to 30% of patients.\n\nAbdominal features\n\nHepatosplenomegaly unrelated to cardiac status is present in approximately 25% of patients.\n\nGenitourinary features \n\nRenal anomalies are present in 10% of patients but are not clinically significant.\nMore than half of male patients have undescended testes.\n\nSkeletal features\n\nJoint laxity is present in more than half of patients.\nTalipes equinovarus, radioulnar synostosis, cervical spine fusion, and joint contractures are less common findings.\n\nSkin findings \n\nLymphedema\nProminent pads of fingers and toes\nFollicular keratosis of the face and extensor surfaced\nMultiple lentigines\n\nNeurologic findings\n\nHypotonia\nSeizure disorder\nUnexplained peripheral neuropathy (infrequent)', 'role': 'assistant'}]