About klinefelter syndrome
What is klinefelter syndrome?
Klinefelter syndrome facts
- Klinefelter syndrome, also known as the XXY condition, is a term used to describe males who have an extra X chromosome in most of their cells.
- About one of every 500 males has an extra X chromosome, but many don't have any symptoms.
- Symptoms depend on how many XXY cells a man has, how much testosterone is in his body, and his age when the condition is diagnosed.
- As XXY males enter puberty, they may have a taller, less muscular body, less facial and body hair, and broader hips than other boys. As teens, XXY males may have larger breasts, weaker bones, and a lower energy level than other boys.
- XXY adult males look similar to males without the condition, although they are often taller and may have autoimmune disorders, breast cancer, vein diseases, osteoporosis, and tooth decay.
- XXY males can have normal sex lives, but they usually make little or no sperm and are infertile.
- The XXY chromosome pattern cannot be changed. Treatments involve physical, speech, occupational, behavioral, mental health, and family therapists, and testosterone replacement therapy (TRT).
What is Klinefelter syndrome?
Klinefelter syndrome, also known as the XXY condition, is a term used to describe males who have an extra X chromosome in most of their cells. Instead of having the usual XY chromosome pattern that most males have, these men have an XXY pattern. Klinefelter syndrome is named after Dr. Henry Klinefelter, who first described a group of symptoms found in some men with the extra X chromosome. Even though all men with Klinefelter syndrome have the extra X chromosome, not every XXY male has all of those symptoms.
Because not every male with an XXY pattern has all the symptoms of Klinefelter syndrome, it is common to use the term XXY male to describe these men, or XXY condition to describe the symptoms.
Scientists believe the XXY condition is one of the most common chromosome abnormalities in humans. About one of every 500 males has an extra X chromosome, but many don't have any symptoms.
What are the symptoms for klinefelter syndrome?
Signs and symptoms of Klinefelter syndrome vary widely among males with the disorder. Many boys with Klinefelter syndrome have few noticeable signs, and the condition may go undiagnosed until adulthood. For others, the condition has a noticeable effect on growth or appearance.
Signs and symptoms of Klinefelter syndrome also vary by age.
Signs and symptoms may include:
- Weak muscles
- Slow motor development — taking longer than average to sit up, crawl and walk
- Delay in speaking
- Quiet, docile personality
- Problems at birth, such as testicles that haven't descended into the scrotum
Boys and teenagers
Signs and symptoms may include:
- Taller than average stature
- Longer legs, shorter torso and broader hips compared with other boys
- Absent, delayed or incomplete puberty
- After puberty, less muscle and less facial and body hair compared with other teens
- Small, firm testicles
- Small penis
- Enlarged breast tissue (gynecomastia)
- Weak bones
- Low energy levels
- Tendency to be shy and sensitive
- Difficulty expressing thoughts and feelings or socializing
- Problems with reading, writing, spelling or math
- Low sperm count or no sperm
- Small testicles and penis
- Low sex drive
- Taller than average height
- Weak bones
- Decreased facial and body hair
- Less muscular than normal
- Enlarged breast tissue
- Increased belly fat
When to see a doctor
See a doctor if you or your son has:
- Slow development during infancy or boyhood. Delays in growth and development can be the first sign of a number of conditions that need treatment — including Klinefelter syndrome. Though some variation in physical and mental development is normal, it's best to check with a doctor if you have any concerns.
- Male infertility. Many men with Klinefelter syndrome aren't diagnosed with infertility until they realize they're unable to father a child.
What are the causes for klinefelter syndrome?
Klinefelter syndrome occurs as a result of a random error that causes a male to be born with an extra sex chromosome. It isn't an inherited condition.
Humans have 46 chromosomes, including two sex chromosomes that determine a person's sex. Females have two X sex chromosomes (XX). Males have an X and a Y sex chromosome (XY).
Klinefelter syndrome can be caused by:
- One extra copy of the X chromosome in each cell (XXY), the most common cause
- An extra X chromosome in some of the cells (mosaic Klinefelter syndrome), with fewer symptoms
- More than one extra copy of the X chromosome, which is rare and results in a severe form
Extra copies of genes on the X chromosome can interfere with male sexual development and fertility.
What are the treatments for klinefelter syndrome?
If you or your son is diagnosed with Klinefelter syndrome, your health care team may include a doctor who specializes in diagnosing and treating disorders involving the body's glands and hormones (endocrinologist), a speech therapist, a pediatrician, a physical therapist, a genetic counselor, a reproductive medicine or infertility specialist, and a counselor or psychologist.
Although there's no way to repair the sex chromosome changes due to Klinefelter syndrome, treatments can help minimize its effects. The earlier a diagnosis is made and treatment is started, the greater the benefits. But it's never too late to get help.
Treatment for Klinefelter syndrome may include:
- Testosterone replacement therapy. Starting at the time of the usual onset of puberty, testosterone replacement can be given to help stimulate changes that normally occur at puberty, such as developing a deeper voice, growing facial and body hair, and increasing muscle mass and penis size. Testosterone therapy can also improve bone density and reduce the risk of fractures. It will not result in testicle enlargement or improve infertility.
- Breast tissue removal. In males who develop enlarged breasts, excess breast tissue can be removed by a plastic surgeon, leaving a more normal-looking chest.
- Speech and physical therapy. These treatments can help boys with Klinefelter syndrome overcome problems with speech, language and muscle weakness.
- Educational evaluation and support. Some boys with Klinefelter syndrome have trouble learning and socializing and can benefit from extra assistance. Talk to your child's teacher, school counselor or school nurse about what kind of support might help.
- Fertility treatment. Most men with Klinefelter syndrome are unable to father children because few or no sperm are produced in the testicles. For some men with minimal sperm production, a procedure called intracytoplasmic sperm injection (ICSI) may help. During ICSI, sperm is removed from the testicle with a biopsy needle and injected directly into the egg.
- Psychological counseling. Having Klinefelter syndrome can be a challenge, especially during puberty and young adulthood. For men with the condition, coping with infertility can be difficult. A family therapist, counselor or psychologist can help work through the emotional issues.
What are the risk factors for klinefelter syndrome?
Klinefelter syndrome stems from a random genetic event. The risk of Klinefelter syndrome isn't increased by anything a parent does or doesn't do. For older mothers, the risk is higher but only slightly.