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: Surgery
A child presents with anti-mongoloid slant, pulmonary stenosis, sho stature and undescended testis. The most likely diagnosis is: 
Select and explain. 
A. Klinefelter syndrome, B. Noonan syndrome, C. Turner syndrome, D. Down syndrome
B: Noonan syndrome
Answer: B: Noonan syndrome 
Explanation: Noonan syndrome - Autosomal dominant gene with variable expressivity, the gene has mapped to chromosome 12q. Most common abnormalities are - sho stature, webbing of neck, pectus carinatum or pectus excavatum, cubitus valgus, right sided congenital hea disease *Hypeelorism, epicanthus, downward slanted palpebral fissure, ptosis, micrognathia and ear abnormality *Clinodactyly, moderate mental retardation, high frequency sensorineural hearing loss is common *The cardiac defect Q is most often pulmonary valvular stenosis, hyperophic cardiomyopathy or ASD *Low clotting factors XI or XII, ALL and CML have been described *A few patient with neurofibromatosis I and features of Noonan syndrome were subsequently repoed as havinq Turner syndrome, Male frequently have Cryptorchidism and small testes, they may be hypogonadal or normal.