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
Klinefelter syndrome is diagnosed by 
Select and explain. 
A. Karyotyping, B. USG abdomen, C. Triple test, D. Echocardiography
A: Karyotyping
Answer: A: Karyotyping 
Explanation: Persons with Klinefelter syndrome are identified with the help of karyotyping. 80% of children with klinefelter syndrome have a male karyotype of X-47,XXY,while the remaining 20% have multiple sex mosaicism or structurally abnormal X chromosome Reference: (Nelson TB of pediatrics pg 410 edition 19.