<prompt> What is the abnormality seen in the following karyotype?Gynecomastia with long thin limbsSho stature with webbed neckHigh-pitched cryRound face with protruding tongue  <response>: 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 XXXY; 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 Infeilityazoospermia Ref: Nelson textbook of pediatrics 21st edition Pgno: 671 