Symptoms arising from presence of two or more X chromosomes in males, primarily sterility.Encyclopedia Entry for Klinefelter Syndrome :Klinefelter syndrome. 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.Infertility is the most common symptom of Klinefelter syndrome. Symptoms may include any of the following: 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 Small penis size.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) Semen count Blood tests will be done to check hormone levels including: Estradiol, a type of estrogen Follicle stimulating hormone Luteinizing hormone Testosterone.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. But, an infertility specialist may be able to help. Seeing a doctor called an endocrinologist may also be helpful.These groups can provide more information: The American Association for Klinefelter Syndrome Information and Support (AAKSIS) -- www.aaksis.org National Institute of Health, National Human Genome Research Institute -- www.genome.gov/19519068.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) Autoimmune disorders, such as lupus , rheumatoid arthritis , and Sjogren syndrome Breast cancer in men Depression Learning disabilities, including dyslexia, which affects reading A rare type of tumor called an extragonadal germ cell tumor Lung disease Osteoporosis Varicose veins.Call for an appointment with 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.47 X-X-Y syndrome; XXY syndrome; XXY trisomy; 47,XXY/46,XY; Mosaic syndrome; Poly-X Klinefelter syndrome.Allan CA, McLachlan RI. Androgen deficiency disorders.