Which condition is characterized by tall stature with infertility and sparse body hair in a male patient?

• A. Turner syndrome
• B. Down syndrome
• C. Trisomy 13
• D. Klinefelter syndrome

Answer: (D)

This pattern reflects Klinefelter syndrome, caused by an extra X chromosome in a male (typically 47,XXY). The extra X impairs testicular development, leading to low testosterone and impaired spermatogenesis. That testosterone deficiency produces sparse body hair and reduced secondary sexual characteristics, while infertility arises from azoospermia or severe oligospermia. The body often remains tall with prolonged growth because testosterone’s usual effects on epiphyseal plate closure are blunted. The pituitary responds to low testosterone with elevated gonadotropins (LH and FSH), a sign of hypergonadotropic hypogonadism. Gynecomastia can also be present, and learning difficulties may occur. The other conditions described involve different chromosomal patterns and presentations that don’t match this male with tall stature, infertility, and sparse body hair.