Klinefelter syndrome
MONDO:0006823A 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.
Also known as: 47,XXY syndrome, Klinefelter syndrome, Klinefelter's syndrome, Klinefelter's syndrome, XXY, XXY syndrome, XXY syndrome (Klinefelter syndrome), hypogonadotropic hypogonadism
14 clinical trials for this condition and its sub-types.
Follow this condition — get notified about new trialsBroader categories
-
Can early parent coaching help infants with rare genetic disorders thrive?
Disease control ENROLLING_BY_INVITATIONThis study tests a program called PIXI that coaches parents of infants diagnosed with rare neurogenetic disorders (such as Fragile X, Angelman, or Down syndrome) during the first year of life. The program combines education about the disorder, guided parent-child interaction acti…
Phase: NA • Sponsor: RTI International • Aim: Disease control
Last updated Jul 15, 2026 00:00 UTC
-
Reading the genetic code to understand differences in sex development
Knowledge-focused ENROLLING_BY_INVITATIONThis study aims to find genetic causes of conditions that affect the development of the gonads and genitals, such as hypospadias and ambiguous genitalia. Researchers will use whole exome sequencing to analyze DNA from 300 children and their families. The study also measures how r…
Phase: NA • Sponsor: Boston Children's Hospital • Aim: Knowledge-focused
Last updated Jul 24, 2026 00:00 UTC
-
New study aims to unlock mysteries of sex chromosome disorders in children
Knowledge-focused ENROLLING_BY_INVITATIONThis study follows 300 fetuses and children with sex chromosome disorders to track their growth, organ development, and overall health. Researchers will also look at genetic and gut microbiome factors. The goal is to better understand how these conditions affect children over tim…
Sponsor: University of Aarhus • Aim: Knowledge-focused
Last updated Jun 27, 2026 08:11 UTC
-
Scientists probe genetic secrets of lost fetuses to unravel sex chromosome mysteries
Knowledge-focused ENROLLING_BY_INVITATIONThis study looks at fetuses with sex chromosome disorders (like extra or missing X or Y chromosomes) that were either miscarried or electively aborted. Researchers will analyze the placenta and fetal tissues to see how the chromosome changes affect gene activity and development. …
Sponsor: University of Aarhus • Aim: Knowledge-focused
Last updated Jun 27, 2026 08:09 UTC
-
300 men with klinefelter syndrome to be tracked for decades in landmark study
Knowledge-focused ENROLLING_BY_INVITATIONThis study will follow 300 men with Klinefelter syndrome (an extra X chromosome) who are treated at a Danish hospital. Researchers will collect medical records, scans, and blood samples to map how the condition affects growth, hormones, fertility, heart health, and mental well-be…
Sponsor: Rigshospitalet, Denmark • Aim: Knowledge-focused
Last updated Jun 26, 2026 15:49 UTC