Klinefelter syndrome

Klinefelter syndrome is a genetic abnormality where males have an extra X chromosome, so their genetic endowment would be XXY.

About 1 in 1,000 live-born infants have the XXY variation, but many of them do not develop the syndrome. When the syndrome develops, it is not seen until puberty or later in some cases.

Causes

Males inherit a single X chromosome from their mother and a single Y chromosome from their father. Men with Klinefelter syndrome inherit at least one extra X chromosome.

There is a risk factor that increases the chances of suffering from it: women over 35 years of age.

Symptoms

The most characteristic symptoms are:

• Babies at birth are underweight and have slower motor development
• Their arms and legs are proportionally longer than the body (long limbs, short body)
• They are tall
• Gynecomastia (larger than normal breasts)
• Little facial and body hair
• Underdeveloped testicles and penis
• Inability to produce sperm (infertility)
• Low sexual desire in adult life
• Difficulties in learning, literacy and language
• Normal IQ

Men with Klinefelter syndrome are at increased risk for: diabetes, breast and lung cancer, cardiovascular disease, and osteoporosis.

Diagnosis

To diagnose the syndrome, a karyotype must be performed: a study of the individual's chromosomes. In the case of Klinefelter syndrome, there are 47 chromosomes instead of 46.

The diagnosis can be made at different stages of life:

• Pregnancy: through amniocentesis
• Babies: when undescended testicles and small penis are observed
• Children: with learning disabilities
• Adolescents: when they have excessive breast development
• Adult: when there are fertility problems

Treatment

Treatment consists of supplying the male sex hormone, testosterone. It is administered from the age of 10 or 12 in children and adults. Although it is helpful for many aspects of the syndrome, it cannot reverse infertility.

The benefits of testosterone are: they give the patient greater strength, more muscle and body hair. Increase self-esteem