Disease: Klinefelter syndrome


    Klinefelter syndrome is a genetic condition that results when a boy is born with an extra copy of the X chromosome. Klinefelter syndrome is a common genetic condition affecting males, and it often isn't diagnosed until adulthood.

    Klinefelter syndrome may adversely affect testicular growth, resulting in smaller than normal testicles, which can lead to lower production of testosterone. The syndrome may also cause reduced muscle mass, reduced body and facial hair, and enlarged breast tissue. The effects of Klinefelter syndrome vary, and not everyone has the same signs and symptoms.

    Most men with Klinefelter syndrome produce little or no sperm, but assisted reproductive procedures may make it possible for some men with Klinefelter syndrome to father children.

    Source: http://www.mayoclinic.com


    Signs and symptoms of Klinefelter syndrome vary widely among males with the disorder. Many boys with Klinefelter syndrome have few noticeable signs, and the condition may go undiagnosed until adulthood. For others, the condition has a noticeable effect on growth or appearance.

    Signs and symptoms of Klinefelter syndrome also vary by age.


    Signs and symptoms may include:

    • Weak muscles
    • Slow motor development — taking longer than average to sit up, crawl and walk
    • Delay in speaking
    • Quiet, docile personality
    • Problems at birth, such as testicles that haven't descended into the scrotum

    Boys and teenagers

    Signs and symptoms may include:

    • Taller than average stature
    • Longer legs, shorter torso and broader hips compared with other boys
    • Absent, delayed or incomplete puberty
    • After puberty, less muscle and less facial and body hair compared with other teens
    • Small, firm testicles
    • Small penis
    • Enlarged breast tissue (gynecomastia)
    • Weak bones
    • Low energy levels
    • Tendency to be shy and sensitive
    • Difficulty expressing thoughts and feelings or socializing
    • Problems with reading, writing, spelling or math


    • Low sperm count or no sperm
    • Small testicles and penis
    • Low sex drive
    • Taller than average height
    • Weak bones
    • Decreased facial and body hair
    • Less muscular than normal
    • Enlarged breast tissue
    • Increased belly fat

    When to see a doctor

    See a doctor if you or your son has:

    • Slow development during infancy or boyhood. Delays in growth and development can be the first sign of a number of conditions that need treatment — including Klinefelter syndrome. Though some variation in physical and mental development is normal, it's best to check with a doctor if you have any concerns.
    • Male infertility. Many men with Klinefelter syndrome aren't diagnosed with infertility until they realize they're unable to father a child.

    Source: http://www.mayoclinic.com


    Klinefelter syndrome occurs as a result of a random error that causes a male to be born with an extra sex chromosome. It isn't an inherited condition.

    Humans have 46 chromosomes, including two sex chromosomes that determine a person's sex. Females have two X sex chromosomes (XX). Males have an X and a Y sex chromosome (XY).

    Klinefelter syndrome can be caused by:

    • One extra copy of the X chromosome in each cell (XXY), the most common cause
    • An extra X chromosome in some of the cells (mosaic Klinefelter syndrome), with fewer symptoms
    • More than one extra copy of the X chromosome, which is rare and results in a severe form

    Extra copies of genes on the X chromosome can interfere with male sexual development and fertility.

    Source: http://www.mayoclinic.com


    Your doctor will likely do a thorough physical exam and ask detailed questions about symptoms and health. This may include examining the genital area and chest, performing tests to check reflexes, and assessing development and functioning.

    The main tests used to diagnose Klinefelter syndrome are:

    • Hormone testing. Blood or urine samples can reveal abnormal hormone levels that are a sign of Klinefelter syndrome.
    • Chromosome analysis. Also called karyotype analysis, this test is used to confirm a diagnosis of Klinefelter syndrome. A blood sample is sent to the lab to check the shape and number of chromosomes.

    A small percentage of males with Klinefelter syndrome are diagnosed before birth. This might be identified after a pregnant woman has a procedure to examine fetal cells drawn from the amniotic fluid (amniocentesis) or placenta for another reason, such as being older than age 35 or having a family history of genetic conditions.

    Source: http://www.mayoclinic.com


    Klinefelter syndrome may increase the risk of:

    • Anxiety and depression
    • Infertility and problems with sexual function
    • Weak bones (osteoporosis)
    • Heart and blood vessel disease
    • Breast cancer and certain other cancers
    • Lung disease
    • Endocrine conditions such as diabetes and hypothyroidism
    • Autoimmune disorders such as lupus and rheumatoid arthritis
    • Tooth problems that make dental cavities more likely

    A number of complications caused by Klinefelter syndrome are related to low testosterone (hypogonadism). Testosterone replacement therapy reduces the risk of certain health problems, especially when therapy is started at the beginning of puberty.

    Source: http://www.mayoclinic.com

    Coping and support

    Treatment, health education and social support can greatly benefit individuals with Klinefelter syndrome.

    Boys with Klinefelter syndrome

    If you have a son with Klinefelter syndrome, you can help promote healthy mental, physical, emotional and social development.

    • Learn about Klinefelter syndrome. Then you can provide accurate information, support and encouragement.
    • Monitor your son's development carefully. Seek help for problems you notice, such as trouble with speech or language.
    • Keep regular follow-up appointments with medical professionals. This may help prevent future problems.
    • Encourage participation in sports and physical activities. These activities will help build muscle strength and motor skills.
    • Encourage social opportunities and participation in group activities. These activities can help develop social skills.
    • Work closely with your son's school. Teachers, school counselors and administrators who understand your son's needs can make a big difference.
    • Learn what support is available. For example, ask about special education services, if needed.
    • Connect with other parents. Klinefelter syndrome is a common condition, and you — and your son — aren't alone. Ask your doctor about internet resources and support groups that may help answer questions and ease concerns.

    Men with Klinefelter syndrome

    If you have Klinefelter syndrome, you may benefit from these self-care measures:

    • Work closely with your doctor. Appropriate treatment can help you maintain your physical and mental health and prevent problems later in life, such as osteoporosis.
    • Investigate your options for planning a family. You and your partner may want to talk to a doctor or other health professional about your options.
    • Talk with others who have the condition. There are a number of resources that provide information about Klinefelter syndrome and can offer the perspectives of other men and their partners who cope with the condition. Many men also find it helpful to join a support group.

    Source: http://www.mayoclinic.com

    Risk factors

    Klinefelter syndrome stems from a random genetic event. The risk of Klinefelter syndrome isn't increased by anything a parent does or doesn't do. For older mothers, the risk is higher but only slightly.

    Source: http://www.mayoclinic.com

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