A genetic condition in a male characterized by the presence of at least one extra X chromosome
In humans, the sex chromosomes are the X chromosome and the Y chromosome. The basis of sex determination in humans is on the pair of sex chromosomes present in an individual. For instance, the presence of two X chromosomes characterizes a female whereas the presence of one X chromosome and one Y chromosome is a characteristic of a male. There are instances though when certain individuals have a different set of chromosomal composition. One of them is an individual with XXY chromosomes. This genetic condition is referred to as Klinefelter syndrome.
Klinefelter syndrome is a genetic condition characterized by the presence of at least one extra X chromosome in males. The condition may not be detected early on since most of the symptoms become noticeable at puberty. Males with this condition have less body hair, weaker muscles, greater height, enlarged breasts, broader hips, and small testes. Many of these symptoms are associated with less testosterone produced in males with Klinefelter syndrome than those in males without the extra X chromosome.
The condition is named after Harry Klinefelter, an American rheumatologist and endocrinologist, and the first to identify this condition in 1940.