What is the typical karyotype for a person with Klinefelter syndrome?

Klinefelter syndrome is characterized by the presence of an extra X chromosome in males, which leads to a typical karyotype of 47, XXY. This genetic condition arises from nondisjunction during meiosis, resulting in males that have an additional X chromosome alongside their normal XY chromosome complement. The presence of this extra chromosome disrupts normal development and can lead to a variety of features, including infertility, hypogonadism, and some degree of learning difficulties.

The karyotype indicates the total number of chromosomes and the sex chromosomes present in an individual, which is essential for diagnosing Klinefelter syndrome. Individuals with a karyotype of 45, X, for example, would have Turner syndrome, a condition affecting females characterized by the absence of one X chromosome. A karyotype of 46, XX represents a typical female, while 46, XY is typical for males without any chromosome abnormalities. The presence of the extra X chromosome in Klinefelter syndrome is crucial in understanding the clinical implications and the genetic basis of the condition.