Klinefelter Syndrome
Information, Symptoms, Treatments and Resources
Humans have 46 chromosomes. Chromosomes contain all of your genes and DNA, the building blocks of the body. Two of these chromosomes, the sex chromosomes, determine if you become a boy or a girl. Females normally have two of the same sex chromosomes, written as XX. Males normally have an X and a Y chromosome (written as XY).
Klinefelter syndrome results in males who have at least one extra X chromosome. Usually, this occurs as a result of one extra X (written as XXY).
Klinefelter syndrome is found in about 1 out of every 500-1,000 newborn males. Women who have pregnancies after age 35 are slightly more likely to have a boy with this syndrome than younger women.
The most common symptom is infertility. Other symptoms may include:
- Small, firm testicles
- Small penis
- Only a little bit of pubic, armpit, and facial hair
- Sexual problems
- Enlarged breasts ( gynecomastia)
- Tall height
- Abnormal body proportions (long legs, short trunk)
Adults may come to the doctor because of infertility. School-age children may be brought in to because of learning problems.
The following test results may be found:
- Karyotyping shows 47 XXY.
- Semen count is low.
- Serum testosterone is low.
- Serum luteinizing hormone is high.
- Serum follicle stimulating hormone is high.
- Serum estradiol levels (a type of estrogen) is high.
Testosterone therapy may be prescribed. This can help:
- Increase strength
- Improve appearance of muscles
- Grow body hair
- Improve mood and self esteem
- Increase energy and sex drive
- Improve concentration
Most men with this syndrome are not able to father children. However, there have been some men who have. An infertility specialist may be able to help.
The syndrome is associated with an increased risk of:
- Breast cancer
- Extragonadal germ cell tumor (a rare tumor)
- Lung disease
- Varicose veins
- Osteoporosis
- Autoimmune disorders such as lupus, rheumatoid arthritis, and Sjogren syndrome
- Learning disabilities, despite normal or high IQ
- Dyslexia
- Attention deficient hyperactivity disorder
- Depression
Taurodontism, which is when the teeth have enlarged pulp and a thinning surface, is very common in Klinefelter syndrome. It can be diagnosed by dental x-rays.
Call for an appointment with your health care provider if a boy does not develop secondary sexual characteristics at puberty. A genetics counselor can help explain abnormal chromosome findings. A consultation with an endocrinologist and infertility specialist may also be helpful.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. � 1997- 2008 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
