Klinefelter Syndrome

**Semantic type:** Disease or Syndrome

**Definition:** A sex chromosome disorder caused by the presence of an extra X chromosome in the male karyotype. Affected individuals are infertile and have a small penis and testes. They tend to have tall stature and long legs and may have difficulties with speech and language development. Gynecomastia may be present.

**Synonyms:** - 47,XXY Syndrome - Hypogonadotropic Hypogonadism - Klinefelter syndrome - Klinefelter's Syndrome - Klinefelter's Syndrome, XXY - XXY Syndrome - XXY Syndrome (Klinefelter Syndrome)