BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuKlinefelter syndrome47 X-X-Y syndrome; XXY syndrome; XXY trisomy; 47,XXY/46,XY; Mosaic syndrome; Poly-X Klinefelter syndromeKlinefelter syndrome is a genetic condition that occurs in males when they have an extra X chromosome. Causes Most people have 46 chromosomes. Chromosomes contain all of your genes and DNA, the building blocks of the body. The 2 sex chromosomes (X and Y) determine if you become a boy or a girl. Girls normally have 2 X chromosomes. Boys normally have 1 X and 1 Y chromosome.Klinefelter syndrome results when a boy is born with at least 1 extra X chromosome. This is written as XXY.Klinefelter syndrome occurs in about 1 out of 500 to 1,000 baby boys. Women who get pregnant after age 35 are slightly more likely to have a boy with this syndrome than younger women. Symptoms Infertility is the most common symptom of Klinefelter syndrome. InfertilityInfertility means you cannot get pregnant (conceive). There are 2 types of infertility:Primary infertility refers to couples who have not become preg...ImageRead Article Now Book Mark Article Symptoms may include any of the following:Abnormal body proportions (long legs, short trunk, shoulder equal to hip size) Abnormally large breasts (gynecomastia) GynecomastiaWhen abnormal breast tissue develops in males, it is called gynecomastia. It is important to find out if the excess growth is breast tissue and not ...ImageRead Article Now Book Mark Article Infertility Sexual problems Less than normal amount of pubic, armpit, and facial hair Small, firm testicles TesticlesThe testes are 2 egg-shaped male reproductive organs located in the scrotum. They produce sperm and the male hormone, testosterone.ImageRead Article Now Book Mark Article Tall height Small penis size Exams and Tests Klinefelter syndrome may first be diagnosed when a man comes to the health care provider because of infertility. The following tests may be performed:Karyotyping (checks the chromosomes) KaryotypingKaryotyping is a test to examine chromosomes in a sample of cells. This test can help identify genetic problems as the cause of a disorder or diseas...ImageRead Article Now Book Mark Article Semen countSemen countSemen analysis measures the amount and quality of a man's semen and sperm. Semen is the thick, white fluid released during ejaculation that contains...ImageRead Article Now Book Mark Article Blood tests will be done to check hormone levels, including:Estradiol, a type of estrogen Estradiol, a type of estrogenAn estradiol test measures the amount of a hormone called estradiol in the blood. Estradiol is one of the main types of estrogens.Read Article Now Book Mark Article Follicle stimulating hormone Follicle stimulating hormoneThe follicle stimulating hormone (FSH) blood test measures the level of FSH in blood. FSH is a hormone released by the pituitary gland, located on t...Read Article Now Book Mark Article Luteinizing hormone Luteinizing hormoneThe LH blood test measures the amount of luteinizing hormone (LH) in blood. LH is a hormone released by the pituitary gland, located on the undersid...Read Article Now Book Mark Article TestosteroneTestosteroneA testosterone test measures the amount of the male hormone, testosterone, in the blood. Both men and women produce this hormone. The test described...Read Article Now Book Mark Article Treatment Testosterone therapy may be prescribed. This can help:Grow body hair Improve appearance of muscles Improve concentration Improve mood and self esteem Increase energy and sex drive Increase strength Most men with this syndrome are not able to get a woman pregnant. An infertility specialist may be able to help. Seeing a doctor called an endocrinologist may also be helpful. Support Groups These sources can provide more information on Klinefelter syndrome:Association for X and Y Chromosome Variations -- genetic.org US National Library of Medicine, MedlinePlus -- medlineplus.gov/klinefelterssyndrome.html Possible Complications Enlarged teeth with a thinning surface is very common in Klinefelter syndrome. This is called taurodontism. This can be seen on dental x-rays.Klinefelter syndrome also increases the risk of:Attention deficient hyperactivity disorder (ADHD) Attention deficient hyperactivity disor...Attention deficit hyperactivity disorder (ADHD) is a problem caused by the presence of one or more of these findings: not being able to focus, being ...Read Article Now Book Mark Article Autoimmune disorders, such as lupus, rheumatoid arthritis, and Sjögren syndrome LupusSystemic lupus erythematosus (SLE) is an autoimmune disease. In this disease, the immune system of the body mistakenly attacks healthy tissue. It c...ImageRead Article Now Book Mark Article Rheumatoid arthritisRheumatoid arthritis (RA) is a disease that leads to inflammation of the joints and surrounding tissues. It is a long-term disease. It can also aff...ImageRead Article Now Book Mark Article Sjögren syndromeSjögren syndrome is an autoimmune disorder in which the glands that produce tears and saliva are destroyed. This causes dry mouth and dry eyes. The...ImageRead Article Now Book Mark Article Breast cancer in men Breast cancerBreast cancer is cancer that starts in the tissues of the breast. There are two main types of breast cancer:Ductal carcinoma starts in the tubes (du...ImageRead Article Now Book Mark Article Depression Learning disabilities, including dyslexia, which affects reading A rare type of tumor called an extragonadal germ cell tumor Lung disease Lung diseaseLung disease is any problem in the lungs that prevents the lungs from working properly. There are three main types of lung disease:Airway diseases -...ImageRead Article Now Book Mark Article Osteoporosis OsteoporosisOsteoporosis is a disease in which bones become fragile and more likely to break (fracture).ImageRead Article Now Book Mark Article Varicose veinsVaricose veinsVaricose veins are swollen, twisted, and enlarged veins that you can see under the skin. They are often red or blue in color. They most often appea...ImageRead Article Now Book Mark Article When to Contact a Medical Professional Contact your provider if your son does not develop secondary sexual characteristics at puberty. This includes facial hair growth and a deepening of the voice.A genetics counselor can provide information about this condition and direct you to support groups in your area.Open ReferencesReferencesAllan CA, McLachlan RI. Androgen deficiency disorders. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 139.Matsumoto AM, Anawalt BD, Testicular disorders. In: Melmed S, Auchus, RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 19.Nussbaum RL, McInnes RR, Willard HF. The chromosomal and genomic basis of disease: disorders of the autosomes and sex chromosomes. In: Nussbaum RL, McInnes RR, Willard HF, eds. Thompson & Thompson Genetics in Medicine. 8th ed. Philadelphia, PA: Elsevier; 2016:chap 6.AllVideoImagesTogKaryotyping - illustration Karyotyping is a test used to identify chromosome abnormalities as the cause of malformation or disease. The test can be performed on a sample of blood, bone marrow, amniotic fluid, or placental tissue.KaryotypingillustrationKaryotyping - illustration Karyotyping is a test used to identify chromosome abnormalities as the cause of malformation or disease. The test can be performed on a sample of blood, bone marrow, amniotic fluid, or placental tissue.KaryotypingillustrationRelated Information Breast cancer(Condition)Lung disease(Condition)Varicose veins(Condition)Osteoporosis(Condition)Breast cancer(In-Depth)Osteoporosis(In-Depth) Review Date: 10/27/2020 Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. 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