Which chromosomal pattern is associated with Klinefelter syndrome?

Klinefelter syndrome is characterized by the presence of an extra X chromosome in males, leading to a chromosomal pattern of XXY. This condition results from nondisjunction during meiosis, which causes the failure of homologous chromosomes or sister chromatids to separate properly. As a consequence, individuals with Klinefelter syndrome typically have an atypical male phenotype, often presenting with features such as infertility, testicular atrophy, and sometimes gynecomastia.

The extra X chromosome contributes to a variety of physical and cognitive manifestations, including tall stature and potential developmental delays. The diagnosis is usually confirmed through karyotyping, which reveals the XXY configuration. Understanding the chromosomal basis of Klinefelter syndrome is crucial for recognizing its clinical implications and managing the associated healthcare needs.