Klinefelter Syndrome (KS)

SymptomsAlthough the chromosome variation XXY occurs in approximately 1 out of 1,000 live male births, many men with it do not develop KS. When KS does develop, it usually goes undetected until puberty and sometimes much later. It may present during fetal development as an unexpected finding on an amniocentesis , in childhood as learning problems, in adolescence as excessive breast development, or in adult life as infertility concerns. Babies born with KS often have a smaller birth weight and slower muscle and motor development. Characteristics may include: Tallness with extra long arms and legsAbnormal body proportions (long legs, short trunk)Enlarged breastsLack of facial and body hairSmall firm testesSmall penisLack of ability to produce spermDiminished sex driveSexual dysfunctionLearning disabilitiesPersonality impairmentThe most common findings in males with Klinefelter syndrome are sterility, breast development, incomplete masculine body, and social and/or school learning problems.Although their IQ is normal to borderline, most people with KS also have problems with speech and language. They often learn to speak later than other children do, and learning to read and write may be challenging. Eventually, individuals with KS learn to speak normally but continue to have some difficulty with language throughout their lives. If these difficulties are not treated, social and/or school learning problems arise.

Individuals with KS also have an increased risk of: DiabetesBreast cancerLung cancerCardiovascular diseaseLung diseaseOsteoporosis DiagnosisDiagnosis of the XXY chromosome variation is made with a test called a karyotype, which examines all 23 pairs of chromosomes. In the case of KS, there are usually 47 chromosomes rather than the normal 46. Many men with XXY live their whole lives without knowing they have an extra chromosome. If they do get diagnosed, it is most likely at one of the following times: Before birth, if amniocentesis or chorionic villus sampling (CVS) is doneThese tests may be done if there is a family history of genetic problems, the pregnant woman is over age 35, or there are other medical concerns. Babies or toddlers with undescended testicles or a very small penis Early childhood, when a boy has trouble learning to talk, read, and writeTeenage years, if the breasts grow more than usual and puberty fails to develop normally in other waysAdulthood, during testing for infertility TreatmentTreatment of KS includes: TestosteroneThe main treatment is testosterone. When boys with KS are 10-12 years old, their hormone levels are checked yearly. If their testosterone levels are low, then treatment with testosterone may be helpful. Men diagnosed in adulthood may also benefit from taking the hormone, as well. However, testosterone cannot reverse infertility.

Testosterone is most often given through regular shots in the form of depotestosterone. The benefits of this treatment include: Increased strengthMore muscular, male appearanceGrowth of facial and body hairBetter self-esteemModulation of moodIncreased energyIncreased ability to concentrateGreater sex drive Speech and Language Therapy Treatment of speech and language difficulties should begin in early childhood to avoid social and school learning problems. Treatment may involve: Speech therapySpecial education servicesExtra support and help with learning from parents and teachersSocial skills training and psychological counseling to cope with any negative effects of the speech and language problems PreventionCurrently, there are no known ways of preventing KS. RESOURCES: Klinefelter Syndrome and Associateshttp://www.genetic.org National Institute of Child Health & Human Developmenthttp://www.nichd.nih.gov CANADIAN RESOURCES: Canadian Psychiatric Associationhttp://www.cpa-apc.org Canadian Psychological Associationhttp://www.cpa.ca/cpasite/home.asp References: Klinefelter Syndrome and Associates website. Available at: http://www.genetic.org . Larsen PR. Williams Textbook of Endocrinology. 10th ed. Saunders; 2003.

National Institute of Child Health & Human Development website. Available at: http://www.nichd.nih.gov . Last reviewed January 2008 by Rosalyn Carson-DeWitt, MDPlease be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.