Klinefelter syndrome: clinical features and management

Klinefelter syndrome is a genetic condition where a male child is born with an extra X chromosome, so that his sex chromosomes are XXY rather than XY; some people with Klinefelter syndrome have more than two X chromosomes. Klinefelter syndrome is the result of random error and is not a heritable disease. While many people think of the X chromosome as solely a sex chromosome, it plays a significant role in bodily functioning, impacting brain development and growth in addition to sexual functioning. Mental retardation and phenotypic abnormalities are associated with Klinefelter syndrome and are "directly related to the number of supernumerary X chromosomes (Chen, 2013). Klinefelter syndrome is a "form of primary testicular failure, with elevated gonadotropin levels due to lack of feedback inhibition by the pituitary gland" (Chen, 2013). This results in an androgen deficiency that causes many of the symptoms associated with Klinefelter's syndrome. Other hormone levels are impacted, as well, with a typical patient with Klinefelter distributing low serum testosterone levels, and high luteinizing and FSH hormone levels (Chen, 2013).

The signs symptoms associated with Klinefelter's syndrome vary by age. In babies the symptoms include: weak muscles, slow motor development, speech delays, and docility. In boys and teenagers the symptoms include: unusual height, different body proportions than most boys, delayed or absent puberty, small or firm testicles, small penis, enlarged breast tissue, low energy levels, shyness, learning problems, and weak bones. In men, additional signs and symptoms include: infertility, decreased facial and body hair, and a decreased sex drive (Mayo Clinic Staff, 2013).

Klinefelter syndrome is diagnosed in two ways. First, hormone levels are examined through blood and urine testing. If hormone levels are not in the normal range, then the doctor may order chromosome analysis. In chromosome/karyotype analysis, a blood sample is examined to determine the number of chromosomes. The presence of an additional X chromosome results in a Klinefelter syndrome diagnosis.

There is no cure for Klinefelter syndrome, but there are treatment options. Testosterone replacement, especially at the time of normal puberty, can allow a boy to undergo the normal changes associated with puberty. Enlarged breast tissue can be removed. Speech therapy can help a patient overcome language delays, and physical therapy can assist patients dealing with motor delays. For patients that produce some sperm, intracytoplasmic sperm injection can be used as a means of treating infertility. Finally, counseling is a treatment option aimed at helping a patient deal with the impact of the syndrome.

There is no risk of inheritance of Klinefelter syndrome. It is not an inherited disorder, but the result of random changes. The risk of Klinefelter syndrome for any male baby is somewhere in the range of 1 in 500 to 1 in 1,000. This risk remains the same regardless of whether or not the father has the syndrome.