Which karyotype is associated with Klinefelter syndrome?

Which karyotype is associated with Klinefelter syndrome?

• A. 47XXY
• B. 46XY
• C. 46XX
• D. 47XYY

Answer: (A)

Klinefelter syndrome occurs when a male has an extra X chromosome, giving the karyotype 47,XXY. This arises from nondisjunction during the formation of gametes and leads to a male with two X chromosomes and one Y. Clinically, this results in features like hypogonadism, reduced fertility, and often taller stature with breast tissue development. The other patterns don’t match Klinefelter: 46,XY is a typical male chromosome set; 46,XX is typical female; 47,XYY is a male with an extra Y chromosome and presents differently. Thus, the karyotype with two X chromosomes and one Y best identifies Klinefelter syndrome.

Klinefelter syndrome occurs when a male has an extra X chromosome, giving the karyotype 47,XXY. This arises from nondisjunction during the formation of gametes and leads to a male with two X chromosomes and one Y. Clinically, this results in features like hypogonadism, reduced fertility, and often taller stature with breast tissue development. The other patterns don’t match Klinefelter: 46,XY is a typical male chromosome set; 46,XX is typical female; 47,XYY is a male with an extra Y chromosome and presents differently. Thus, the karyotype with two X chromosomes and one Y best identifies Klinefelter syndrome.