Klinefelter’s syndrome, also 47,XXY or XXY syndrome, is a genetic disorder in which there is at least one extra X chromosome to a normal human male karyotype, for a total of 47 chromosomes rather than the 46 found in genetically normal humans. While females have an XX chromosomal makeup, and males an XY, individuals with Klinefelter syndrome have at least two X chromosomes and at least one Y chromosome. Because of the extra chromosome, individuals with the condition are usually referred to as “XXY males”, or “47,XXY males”.
This chromosome constitution (karyotype) exists in roughly between 1:500 to 1:1000 live male births but many of these people may not show symptoms. If the physical traits associated with the syndrome become apparent, they normally appear after the onset of puberty. (Adapted from Wikipedia)
Klinefelter’s syndrome karyotype 47,XXY
Klinefelter’s syndrome 47,XXY. This male has an extra X chromosome. Symptoms include deficiency of male hormones and underdeveloped secondary male characteristics, breast enlargement, small testes, infertility due to lack of sperm, and various psychopathological disorders.