Klinefelter syndrome is a genetic condition that affects males. Klinefelter syndrome occurs when a boy is born with one or more extra X chromosomes. Most males have one Y and one X chromosome. Having extra X chromosomes can cause a male to have a variety of physical traits.
Many men with Klinefelter syndrome do not have obvious symptoms. Others have sparse body hair, enlarged breasts, and wide hips. In almost all men, the testicles remain small. In some men, the penis does not reach adult size.
Current as ofMay 30, 2018
Author: Healthwise Staff John Pope, MD, MPH - Pediatrics Martin J. Gabica, MD - Family Medicine Stephen H. LaFranchi, MD - Pediatric Endocrinology Kathleen Romito, MD - Family Medicine
Medical Review:John Pope, MD, MPH - Pediatrics & Martin J. Gabica, MD - Family Medicine & Stephen H. LaFranchi, MD - Pediatric Endocrinology & Kathleen Romito, MD - Family Medicine