This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetic and genetic disorders, Subject name: Pediatrics
[{'content': 'What is the abnormality seen in the following karyotype? \nSelect and explain. \nA. Gynecomastia with long thin limbs, B. Sho stature with webbed neck, C. High-pitched cry, D. Round face with protruding tongue', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The above karyotype- 47, XXY, is suggestive of Klinefelter&;s syndrome in which gynecomastia and long thin limbs are seen. Klinefelter&;s syndrome: Most common sex aneuploidy in males Classically karyotype is 47,XXY, Other variants can have 48,XXXY; rarel, 49 XXXXY; or mosaics with some cells containing normal 46, XY and others 47,XXY Results from meiotic nondisjunction of sex chromosomes (mostly during 1st meiotic division) Clinical features: Dispropoionately long arms and legs Mitral valve prolapse Mental retardation; IQ: 60-80 Minor development and learning disabilities Lack of secondary sexual characteristics (due to a decrease in androgen production) Gynecomastia Higher risk of breast carcinoma Testicular dysgenesis Infeility/azoospermia Ref: Nelson textbook of pediatrics 21st edition Pgno: 671', 'role': 'assistant'}]