Aalborg University Hospital
Aalborg, Denmark
RecruitingKlinefelter's syndrome
Testosterone Treatment for Boys with Klinefelter Syndrome: A Study on Body Composition Changes During Puberty
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What is this trial about?
A plain-language summary of the goals, design and what participants do
This clinical trial is focused on studying Klinefelter syndrome, a genetic condition that affects males and is characterized by an extra X chromosome. The study will explore the effects of testosterone treatment during puberty in boys with this condition. The treatment involves using a gel called AndroGel 1%, which is applied to the skin. Some participants will receive a placebo, which is a gel that looks the same but does not contain the active ingredient.
The purpose of the study is to evaluate how two years of testosterone replacement therapy can affect body composition, which includes changes in body fat and muscle mass. Participants will be monitored for various health indicators, including growth and development during puberty, hormone levels, and bone health. The study will also assess other factors such as cholesterol levels, blood sugar, and overall physical development.
Throughout the study, participants will undergo regular health assessments, including scans and blood tests, to track changes in their bodies. The study aims to provide valuable insights into how testosterone treatment can benefit boys with Klinefelter syndrome during their critical developmental years. The trial is expected to continue until the end of 2029.
The research process
The trial runs in 10 steps – from screening to follow-up. Each step says what happens and what the team monitors.
Who can join the trial?
5 criteria
- Boys with **Klinefelter syndrome**. This is a condition where a boy has an extra X chromosome, making it 47,XXY instead of the usual 46,XY.
- Age between 10 and 14 years old.
- **LH** (Luteinizing Hormone) levels must be higher than +2 standard deviations. This means the hormone level is higher than what is typically expected for boys of the same age. This is measured using a very sensitive test.
- **Free T** (Free Testosterone) levels must be less than +2 standard deviations. This means the testosterone level is lower than what is typically expected for boys of the same age.
- Parents must provide signed consent for their child to participate in the study.
Who cannot join the trial?
4 criteria
- Individuals who do not have **Klinefelter syndrome**. This is a condition where a male is born with an extra X chromosome.
- Individuals who are not male. The study is only for males.
- Individuals who are not in the age range specified for the study. The study is for a specific age group.
- Individuals who are not considered part of a vulnerable population. The study is for those who are considered vulnerable.
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Verified sites
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Verified Verified Aarhus University Hospital
Aarhus, DenmarkVerified Odense University Hospital
Odense, Denmark
Trial locations
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Investigated drugs
Testosterone is a hormone therapy used in this study to evaluate its effects on boys with Klinefelter syndrome during puberty. The therapy aims to assess changes in body composition over a two-year period.
What is already known about the treatment
Testosterone – Testosterone is administered as an injection or topical gel, and it is currently being studied for its effects during puberty in boys with Klinefelter syndrome. This hormone is well-documented in medical literature as a key treatment for conditions involving low testosterone levels. The main therapeutic indication for testosterone in this study is to address changes in body composition associated with Klinefelter syndrome. At the molecular level, testosterone works by binding to androgen receptors, influencing the expression of specific genes that regulate male characteristics and body composition. It is classified pharmacologically as an androgen and anabolic steroid.
Investigated diseases
Klinefelter Syndrome – Klinefelter syndrome is a genetic condition that affects males, typically caused by an extra X chromosome, resulting in a 47,XXY karyotype. This condition can lead to physical, developmental, and hormonal changes, often becoming noticeable during puberty. Common features include reduced muscle mass, less facial and body hair, and enlarged breast tissue. Individuals may also experience learning difficulties and challenges with speech and language development. The syndrome can affect fertility, with many affected individuals having low testosterone levels and reduced sperm production. The progression of symptoms can vary widely among individuals, with some experiencing more pronounced effects than others.
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Trial detailsLast updated 2 Oct 2026
sourced from the EU Clinical Trials Register and site verification
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