- Causes and risk factors
- Examinations and diagnosis
- Disease course and prognosis
Klinefelter syndrome: description
Klinefelter syndrome is a genetic disease that affects only men. They have at least one so-called sex chromosome too much in their cells. The term XXY syndrome is also common.
Klinefelter syndrome is referred to as a syndrome because there are several signs of the disease that occur simultaneously and are related. It is also called a symptom complex. The Klinefelter syndrome features were first introduced in 1942 by the US physician Dr. Harry Klinefelter described.
Klinefelter syndrome: occurrence
Klinefelter patients are always male. About one boy in 500 to 1000 live births is statistically affected by Klinefelter syndrome. Statistical calculations suggest that approximately 80,000 men throughout Germany suffer from Klinefelter syndrome. With only about 5,000 confirmed cases, one suspects a high number of unreported cases.
Klinefelter syndrome is the most common male chromosome aberration and the most common genetic cause of male infertility.To the table of contents
Klinefelter syndrome: symptoms
The Klinefelter syndrome is individually very differently pronounced and can affect many different organ systems. Most of the childhood of the affected runs inconspicuous. During this time, symptoms may show up like:
- delayed linguistic and motor development
- Learning difficulties with often normal intelligence
- Tall growth with long legs
Frequently, the Klinefelter syndrome is noticeable only in puberty. This usually occurs delayed or not at all:
- The beard and the secondary hair stay out or are sparse.
- The voice break is missing: the patients keep a high voice.
- The sex drive (libido) is diminished
- The testicle volume (the testicle size) remains low
- The men are not capable of reproduction
- Body fat distribution is more female
In addition, further problems can occur:
- Osteoporosis (bone loss)
- muscle weakness
- Diabetes mellitus (diabetes)
- Thrombosis (closure of vessels)
- Tiredness, listlessness
- Gynecomastia (enlargement of the mammary glands)
Klinefelter syndrome: causes and risk factors
To better understand the Klinefelter syndrome, here are some explanations. Klinefelter syndrome is based on chromosome aberration. This is understood by physicians that the number or structure of the chromosomes is disturbed. On the chromosomes are stored our genetic information. Normally there are 46 chromosomes in each cell. These include two sex chromosomes. In the female karyotype (chromosome set), they are referred to as XX, in the male as XY. A normal karyotype is accordingly described as 46, XX and 46, XY, respectively. Klinefelter syndrome has more than 46 chromosomes.
Klinefelter Syndrome: Different types of karyotypes
Different karyotypes can lead to Klinefelter syndrome:
- 47, XXY: About 80 percent of the patients have an additional X chromosome in all body cells.
- 46, XY / 47, XXY: Some patients have cells with normal and altered sets of chromosomes in their bodies. This is called mosaic.
- 48, XXXY; 48, XXYY; 49, XXXXY: There are special cases in which there is not just one extra X chromosome in the cells, but several. Additional Y chromosomes are also possible.
How does Klinefelter syndrome develop?
The cause of Klinefelter syndrome is the maturation of the father's sperm or the maturing of the mother's eggs. In so-called meiosis, the chromosome pairs (XX in the egg cell, XY in the sperm cell) are separated. If this does not happen, a pair of chromosomes is completely passed on and the Klinefelter syndrome develops.
Due to the double X chromosome, the formation of testosterone in the testes is disturbed. Since the male sex hormone testosterone is not only important for the development of the sexual organs and characteristics, but takes over various tasks in the metabolism of humans, the Klinefelter syndrome symptoms are so diverse. In addition, the rest of the X chromosome is partially suppressed. This mechanism varies in severity from patient to patient and ensures a different degree of symptom severity.To the table of contents
Klinefelter syndrome: examinations and diagnosis
Due to mild childhood symptoms, Klinefelter syndrome is often diagnosed only during adolescence and sometimes even as early as unwanted childlessness in adulthood.
At times of compulsory military service affected men in the so-called muster by a small testicle volume. Nowadays, the Klinefelter syndrome is mainly diagnosed at the check-up of adolescents with the pediatrician, the J1. Depending on the age, there is treatment by the pediatrician, endocrinologist or andrologist - sometimes also by several specialties together.