Klinefelter syndrome: description
Klinefelter syndrome is a genetic disease that affects only males. They have at least one so-called sex chromosome too many in their cells. The term XXY syndrome is also common.
Klinefelter syndrome: Incidence
Klinefelter patients are always male. Statistically, about one boy in 500 to 1000 live births is affected by Klinefelter syndrome. Statistical calculations suggest that about 80,000 males are affected by Klinefelter syndrome throughout Germany. With only about 5000 confirmed cases, a high number of unreported cases is suspected.
Klinefelter syndrome: symptoms
Klinefelter syndrome varies greatly in severity from person to person and can affect many different organ systems. In most cases, the childhood of those affected is unremarkable. During this time, symptoms may appear such as:
- delayed linguistic and motor development
- Learning difficulties with often normal intelligence
- tall stature with long legs
- Beard growth and secondary hair are absent or sparse.
- Vocal change is absent: patients retain a high-pitched voice.
- The sex drive (libido) is diminished.
- Testicular volume (testicular size) remains low
- The men are not fertile
- The body fat distribution is more feminine
In addition, there may be other problems:
- Anaemia (anemia)
- Osteoporosis (bone loss)
- Muscle weakness
- Diabetes mellitus (diabetes)
- Thrombosis (occlusion of blood vessels)
- Fatigue, listlessness
Klinefelter syndrome: Causes and risk factors
To better understand Klinefelter syndrome, here are some definitions. Klinefelter syndrome is caused by a chromosomal aberration. Doctors understand this to mean that the number or structure of the chromosomes is disturbed.
In Klinefelter syndrome, more than 46 chromosomes are present.
Klinefelter syndrome: Different karyotypes
Different karyotypes can lead to Klinefelter syndrome:
- 47, XXY: In about 80 percent of the pateints an additional X chromosome is present in all body cells.
- 46, XY/47, XXY: Some patients have cells with normal and with altered chromosome set in their body. This is called mosaicism.
How does Klinefelter syndrome develop?
The Klinefelter syndrome cause lies in the maturation of the father’s sperm cells or the maturation of the mother’s egg cells.
In the so-called meiosis, the chromosome pairs (XX in the egg cell, XY in the sperm cell) are separated. If this does not happen, one chromosome pair is passed on completely and Klinefelter syndrome develops.
In addition, the remaining X chromosome is partially suppressed. This mechanism varies in severity from patient to patient and results in varying degrees of symptom expression.
Klinefelter syndrome: examinations and diagnosis
Due to the mild symptoms in childhood, Klinefelter syndrome is often not diagnosed until puberty and sometimes not until unwanted childlessness in adulthood.
Depending on the age, treatment is carried out by a pediatrician, endocrinologist or andrologist – sometimes by several specialists together.
Klinefelter syndrome: Diagnostics
In order to make the diagnosis of Klinefelter syndrome, the doctor first asks the patient in detail about his medical history (anamnesis). Among other things, he is likely to ask the following questions:
- Did you have trouble keeping up at school?
- Do you often feel listless?
- When did your puberty begin?
Klinefelter syndrome: Physical examination
The doctor then examines the patient physically. He first pays attention to the external appearance, especially the body proportions. Is the patient tall? Does he have longer-than-average legs? In addition, the doctor examines the body hair and the mammary gland.
The size of the testicles is also measured. This is usually significantly reduced in Klinefelter patients.
Klinefelter syndrome: blood test
In addition, the blood cells taken can be viewed under a microscope and the number as well as structure of the chromosomes can be analyzed. Thus, XXY syndrome can be easily detected because instead of two sex chromosomes, there are (at least) three.
Klinefelter syndrome: prenatal examinations
Prenatal diagnostics includes invasive examinations such as amniocentesis: The doctor takes a small sample of the amniotic fluid from the pregnant woman. This contains fetal cells whose genetic material (DNA) can be analyzed for various chromosomal changes (anomalies) such as Klinefelter syndrome. The disadvantage of invasive prenatal examinations such as amniocentesis is that they can cause a miscarriage.
If a Klinefelter syndrome is actually detected in the unborn child by prenatal diagnostics, this is not a reason to terminate the pregnancy! The symptoms of those affected are usually mild and not life-threatening.
Klinefelter syndrome: Treatment
Klinefelter syndrome cannot be cured because it is caused by a chromosomal aberration. This cannot be influenced.
Whether a gel, patch or syringe is used also depends on the patient’s preferences. Gels have the advantage of not being painful. However, they must be applied daily. Patches should be changed every two days. Syringes come in the form of depot injections that only need to be administered every four weeks to three months.
Klinefelter’s syndrome: therapy control
The effectiveness of testosterone treatment should be monitored regularly by blood sampling. For this purpose, the values for testosterone and also other hormones such as LH, FSH and estradiol are monitored.
Successful testosterone therapy is reflected in increased performance and reduced fatigability, as well as in the prevention of osteoporosis, diabetes mellitus and muscle weakness.
Klinefelter syndrome: disease course and prognosis
Klinefelter syndrome usually has mild symptoms. Through consistent testosterone therapy and targeted support at school, patients lead a balanced and self-determined life.
Patients with Klinefelter syndrome have average intelligence. Nevertheless, they often need more time to learn new things. Speech and motor development should be encouraged early through speech therapy and occupational therapy.
Klinefelter syndrome: desire for children
To enable Klinefelter syndrome patients to father children, sperm cells can be removed from the testicles in early adolescence.
Parents of a child with Klinefelter syndrome do not have an increased risk that another child will also have the disease.
