Klinefelter syndrome, with the karyotype 47,XXY, is one of the commonest types of congenital chromosomal disorder in males. With an incidence of 0.1% to 0.2% of newborn male infants, it often causes hypogonadism and infertility. Although with different severity, most patients have normal lifespan as general public. Here we present a brief introduction to the common knowledge of Klinefelter syndrome.
