Last updated on July 27th, 2017 at 10:01 am

Klinefelter syndrome is one of the groups of conditions which affect the health of males who are born with at least one extra X chromosome. Chromosomes, found in all body cells, contain genes. Genes provide specific instructions for body characteristics and functions. For example, some genes will generally determine height and hair color. However, other genes influence language skills and reproductive functions. Each person typically has 23 pairs of chromosomes. One of these pairs (sex chromosomes) determines a person’s sex. A baby with two X chromosomes (XX) is female. A baby having one X chromosome and one Y chromosome (XY) is male.

What are the Causes of Klinefelter’s Syndrome?

Klinefelter’s Syndrome occurs as a result of an error during the formation of an egg or a sperm that results in a person having an XXY combination or 47 chromosomes instead of the normal 46.

Also, Klinefelter’s Syndrome is caused by the presence of an additional X chromosome. This error usually occurs when the chromosomes are distributed during the division of the egg or the sperm. In more than half of the cases, few of the extra X chromosome is contributed by the father.

Causes of Klinefelter's Syndrome

Very little is known about the role of the mother’s age in bringing about this condition. Women who are 35 and older have the greatest risk of having children with Klinefelter’s syndrome. Scientists are not sure what other factors increase the risk as the error that produces the extra chromosome occurs at random.

  • Males with Klinefelter’s Syndrome have normal appearance at birth with normal looking male genitalia.
  • Right from childhood the boys with KS are approximately 2- 4.5 inches taller than boys of similar age.
  • Most prepubertal boys with the condition have disproportionately long legs.


  • Abnormal body proportions (long legs, short trunk, shoulder equal to hip size)
  • Abnormally large breasts (gynecomastia)
  • Infertility
  • Sexual problems
  • Less than normal amount of pubic, armpit, and facial hair
  • Small, firm testicles
  • Tall height.

Diagnosis and Treatment for Klinefelter syndrome

Your doctor will likely do a thorough physical exam and ask detailed questions about symptoms and health. This will include by examining the genital area and chest, performing tests to check reflexes, and assessing development and functioning.

The main tests used to diagnose Klinefelter syndrome are:

Hormone testing

Hormone testing

The blood and also urine sample generally reveals abnormal hormone levels that are a sign of Klinefelter syndrome.

Chromosome analysis

Also called karyotype analysis, this test is used to confirm a diagnosis of Klinefelter syndrome. A blood sample is sent to the lab to check the shape and number of chromosomes.

Testosterone replacement therapy

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

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 in learning and also in 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

Speech and physical therapy

Most of the men who are suffering 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 an ICSI, sperm is removed from the testicle with a biopsy needle and it is injected directly into the egg.

Psychological counseling

Psychological counseling

Having Klinefelter syndrome is a risky 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.

Because of these medical conditions and their complications, a person with Klinefelter syndrome is at increased risk of premature death. Remember, regular checkups help ensure that any changes in health are noted and treated, if needed. The doctor may also schedule certain screening tests to look for problems before certain Klinefelter syndrome symptoms occur.