Klinefelter syndrome
MONDO:0006823Mondo
Findings
No curated finding names Klinefelter syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
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.
Definition from the Mondo Disease Ontology (MONDO:0006823), read 2026-09-29. CC BY 4.0.
Features
1 feature
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, hp/releases/2026-09-01.
- AzoospermiaMondoHP:0000027
Where it sits
Other names
5 names
Resolves to: Klinefelter syndrome
- Also called
- 47,XXY syndromeKlinefelter's syndromeKlinefelter's syndrome, XXYXXY syndromeXXY syndrome (Klinefelter syndrome)