Karyotype of Klinefelter syndrome is-

Klinefelter syndrome is the most common chromosomal disorder associated with male hypogonadism and infertility. It is defined classically by a 47, XXY Karyotype with variants demonstrating additional X and Y chromosomes. (other variants can have 48 XXXY, rarely 49 XXXXY or mosaics can be there with some cells containing normal 46, XY and others 47, XXY). Classically, it results from meiotic nondisjunction of sex chromosomes (40% during spermatogenesis and 60% during oogenesis). Mostly, non-disjunction occur during 1st meiotic division.