XX male syndrome
Overview
Overview
XX male syndrome (also called de la Chapelle syndrome, for a researcher who characterized it in 1972[1]) is a rare sex chromosomal disorder. Usually it is caused by unequal crossing over between X and Y chromosomes during meiosis.
It is less common than Klinefelter syndrome.[2]
Presentation
Presentation
Symptoms include small testes, gynecomastia and sterility. Many individuals with this condition also have effeminate characteristics.
Pathophysiology
Pathophysiology
Men typically have one X chromosome and one Y chromosome in each diploid cell of their bodies. Women typically have two X chromosomes.
So-called XX males have two X chromosomes; thus they are genetically female but otherwise appear to be male.
References
References
- ↑ de la Chapelle A (1972). “Analytic review: nature and origin of males with XX sex chromosomes”. Am J Hum Genet. 24 (1): 71–105. PMID 4622299.
- ↑ Vorona E, Zitzmann M, Gromoll J, Schüring AN, Nieschlag E (2007). “Clinical, endocrinological, and epigenetic features of the 46,XX male syndrome, compared with 47,XXY Klinefelter patients”. J. Clin. Endocrinol. Metab. 92 (9): 3458–65. doi:10.1210/jc.2007-0447. PMID 17579198. Unknown parameter
|month=ignored (help)
Looking for the patient version?
© 2026 MyEClinic – IFTM Institut für Telematik in der Medizin GmbH