- Klinefelter's syndrome
- XXY syndrome
Your QuestionWe have just been told that our 2.5 year old grandson has Klinefelter syndrome. We know very little about this condition and how it will affect him and his family in the future. Where can we find additional information? How can we find a health professional to discuss this in more detail?
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Because XXY males do not really appear different from other males and because they may not have any or mild symptoms, XXY males often don't know they have Klinefelter syndrome (KS). Whether or not a male with KS has visible symptoms depends on many factors, including how much testosterone his body makes, if he is mosaic (with both XY and XXY cells), and his age when the condition is diagnosed and treated. Symptoms may include:
- Abnormal body proportions (long legs, short trunk, narrower shoulders and wider hips)
- Breast growth (gynecomastia)
- Infertility: Nearly all men with KS are unable to father a biologically-related child without help from a fertility specialist.
- Decreased sexual interest
- Less than normal amount of pubic, armpit, and facial hair
- Small, firm testicles
- Tall height
Boys with Klinefelter syndrome may also have learning disabilities and difficulty with speech and language development. They tend to be quiet, sensitive, and unassertive, but personality characteristics vary among males with this condition. 
Management options available to individuals with signs and symptoms of Klinefelter syndrome may include:
- Educational interventions – As children, many individuals with Klinefelter syndrome qualify for special services to help them in school. Teachers can also help by using certain methods in the classroom, such as breaking bigger tasks into small steps.
- Therapeutic options – A variety of therapists, such as physical, speech, occupational, behavioral, mental health, and family therapists, can often help reduce or eliminate some of the symptoms of Klinefelter syndrome such as poor muscle tone, speech and language problems, or low self-confidence.
- Medical management – About half of individuals with KS have low testosterone levels, which may be raised by taking supplemental testosterone. Having a more normal testosterone level can help individuals develop bigger muscles, a deeper voice, and facial and body hair. Many healthcare providers recommend testosterone therapy when a boy reaches puberty. However, not all males with KS benefit from testosterone therapy, and this therapy also may not be suitable for some individuals depending on gender identity. Some individuals may opt to have breast removal or reduction surgery.
Babies with the 47,XXY form of Klinefelter differ little from healthy children. The results of one study on non-mosaic XXY infants younger than 2 years indicated that most XXY babies had normal external genitalia and facial features, with height and weight in the normal range. Genetic testing had been performed due to a delay in walking and/or speech. Early detection of Klinefelter syndrome is shown to be important to monitor potential developmental problems. 
Boys with the 47,XXY karyotype may struggle through adolescence with academics, various frustrations, and, in a few instances, serious emotional or behavioral difficulties. However, most move toward full independence from their families as they enter adulthood. Some have completed graduate education and have a normal level of functioning. Lifespan is not affected by Klinefelter syndrome. 
Advocacy organizations can be a helpful source of additional information and support for individuals, friends and family members with Klinefelter syndrome. A list of advocacy organizations for Klinefelter syndrome can be found under the GARD's Support Group tab.
The following online resources can help you find a genetics professional in your community:
- The National Society of Genetic Counselors provides a searchable directory of US and international genetic counseling services.
- The American College of Medical Genetics has a searchable database of US genetics clinics.
- The University of Kansas Medical Center provides a list of US and international genetic centers, clinics, and departments.
- The American Society of Human Genetics maintains a database of its members, which includes individuals who live outside of the United States. Visit the link to obtain a list of the geneticists in your country, some of whom may be researchers that do not provide medical care.
- Aksglaede L, Link K, Giwercman A, Jørgensen N, Skakkebaek NE, Juul A. 47,XXY Klinefelter syndrome: clinical characteristics and age-specific recommendations for medical management. Am J Med Genet C Semin Med Genet. February 15, 2013; 163C(1):55-63.
- Klinefelter Syndrome: Condition Information. NICHD. November 15, 2013; http://www.nichd.nih.gov/health/topics/klinefelter/conditioninfo/Pages/Default.aspx. Accessed 4/14/2015.
- What are common symptoms of Klinefelter syndrome (KS)?. Eunice Kennedy Shriver National Institute of Child Health and Human Development. http://www.nichd.nih.gov/health/topics/klinefelter/conditioninfo/Pages/symptoms.aspx. Accessed 4/21/2015.
- Kirmse B. Klinefelter syndrome. MedlinePlus Web site. December 11, 2006; http://www.nlm.nih.gov/medlineplus/ency/article/000382.htm. Accessed 4/1/2008.
- Klinefelter syndrome. Genetics Home Reference (GHR). January 2013; http://ghr.nlm.nih.gov/condition/klinefelter-syndrome. Accessed 4/14/2015.
- Learning about Klinefelter syndrome. National Human Genome Research Institute (NHGRI) Web site. May 27, 2008; http://www.genome.gov/19519068. Accessed 12/10/2008.
- What are the treatments for symptoms in Klinefelter syndrome?. NICHD. November 30, 2012; http://www.nichd.nih.gov/health/topics/klinefelter/conditioninfo/Pages/treatments.aspx. Accessed 9/17/2013.
- Klinefelter Syndrome. National Institute of Child Health and Human Development (NICHD) . November 2012; http://www.nichd.nih.gov/health/topics/klinefelter/conditioninfo/Pages/Default.aspx. Accessed 8/21/2013.
- Chen H.. Klinefelter syndrome. e-medicine Medscape. May 17, 2011; http://emedicine.medscape.com/article/945649-followup#a2650. Accessed 6/23/2011.