Klinefelter syndrome, also known as XXY syndrome, is a condition in boys and men that’s caused by an extra X chromosome. It can affect physical and mental development.

Joint hypermobility syndrome causes a person’s joints to bend more than usual. People with a family history of hypermobility may be at more risk. Learn more.

Patients with Klinefelter and triple X syndromes show an increased prevalence of SLE and Sjögren disease, likely due to the synergistic interaction of the extra X chromosomes.

The symptoms with which one can identify Rett Syndrome include slowed growth, particularly of the head (microcephaly), loss of purposeful hand movements, and repetitive motions such as hand ...

Klinefelter syndrome is the most commonly occurring sex-chromosome disorder, and it often goes undiagnosed. In this article the authors discuss the diagnosis and the clinical features and ...

New research uncovers potential treatment for Klinefelter syndrome infertility, highlighting molecular mechanisms and using TGF-β inhibitors to aid sperm production.

Klinefelter syndrome is a genetic condition that occurs when a male is born with an extra copy of the X chromosome, affecting an estimated 1 in 1,000 individuals. Symptoms of Klinefelter syndrome may ...

SMALL testes and aspermia are both characteristic features of Klinefelter's syndrome, and histological examination of the testes usually shows a lack of active spermatogenesis. Biopsies on testes ...

Here is a complete explanation of what Klinefelter is, from the causes, signs or symptoms, to how to treat it.