Klinefelter syndrome is typically diagnosed as an unexpected finding during prenatal diagnostic tests like amniocentesis or chorionic villus sampling (CVS) during pregnancy, or during investigations for male infertility in adulthood. Due to the syndrome often presenting with subtle or mild symptoms, many individuals are thought to remain undiagnosed throughout their lives. While Klinefelter syndrome itself is not a fatal condition, an average reduction of 2 to 5 years in life expectancy can be observed due to certain co-occurring health issues (e.g., cardiovascular diseases or diabetes).