G08: Science Genetic Disorders: Kline-Felter

47,XXY (Klinefelter syndrome) is a chromosomal variation in males where one extra X chromosome is present which then results in a 47,XXY. The extra X chromosome typically affects physical, neurodevelopmental, behavioral and neurocognitive functioning.

Klinefelter's syndrome refers to a sex chromosome anomaly characterized by a surplus of X chromosomes in phenotypic males. The 47 XXY type is the most common chromosomal pattern associated with this disorder; however, mosaic patterns such as 46XY/47XXY and, on rare occasions, variants such as 48XXXY are observed. Klinefelter's syndrome occurs in1 in 500 up to 1 in 1,000 live male births.

Klinefelter syndrome is a common condition that results when a person assigned male at birth has an extra copy of the X sex chromosome instead of the typical XY. Klinefelter syndrome is a genetic condition that occurs before birth, but it often isn't diagnosed until adulthood.