Most genetic abnormalities can be diagnosed during intrauterine development or immediately after birth. The syndrome, first described by Harry Klinefelter and Fuller Albright, is an exception. This disease often occurs almost imperceptibly for decades.
Klinefelter's syndrome - what is it?
The sex of the child is determined by the combination of sex chromosomes. In ovules they are only of one species - X, female. Spermatozoa can carry both similar chromosomes, and male ones - Y. If the egg is fertilized with gamete X, we get a set of XX, and a girl will be born. When the spermatozoon with the male gene becomes the fastest, the XY set is formed, and the family expects the boy.
In some cases, the X or Y chromosome is copied (up to 3 times) and its duplicates are attached to the sexual pair. The most common variant of the combination is XXY - Klinefelter syndrome with such a set is found in boys more often than other species. The considered mutation is inherent in children exclusively male, the girls presented pathology are not sick.
Karyotype, characteristic of Klinefelter's syndrome
Each person has an individual set of chromosomes, consisting of 23 pairs. It is called a karyotype. The last pair (23) is responsible for reproductive functions and sexual characteristics. For a patient with Klinefelter's syndrome, a karyotype is characteristic with the following sets:
The course of the disease and the severity of its symptoms depend on the number of superfluous elements in the 23 pair. Klinefelter's syndrome with karyotypes, including 49 chromosomes, is considered the most severe form of mutation. Still there is a mosaic type of anomaly, when some cells have a normal genetic code (46, XY), and only a few of them have been damaged (47, XXY). In such situations, pathology is accompanied by weak signs and proceeds more easily than other types of the disease.
Frequency of Klinefelter syndrome
The described violation is not uncommon, it is diagnosed in the male population in 0.2% of cases. Klinefelter syndrome occurs in one boy among 500 healthy children. Given the late detection of pathology, this disease is not only the most common genetic mutations, but also one of the most frequent endocrine dysfunction in men.
Klinefelter's syndrome - the causes of
It is not yet established, why some boys have an extra chromosome in the sex pair. There are only theories, which can cause Klinefelter's syndrome - the causes that are supposedly provoking an anomaly:
- viral infections;
- too early or late pregnancy ;
- blood relationship between father and mother;
- adverse ecology.
Klinefelter's syndrome is not inherited. The presence of one or more chromosomes in the sex pair in most situations causes infertility in maturity. A patient with this pathology is not able to have heirs with a similar genetic mutation. Excess chromosome can have both paternal and maternal origin, but in women it is found more often (67% of cases).
Klinefelter's syndrome - symptoms
This disease does not manifest itself in the period of intrauterine development and at an early age. Klinefelter syndrome in newborns can not be visually detected, the infant has normal physical characteristics (height, weight, head circumference) and correctly formed genitalia. The first symptoms of pathology are observed from 5 to 8 years, but they are extremely difficult to detect and associate with the gene mutation:
- susceptibility to viral and bacterial infections;
- slight lag in motor and speech development;
- long legs (in comparison with the trunk);
- high waist;
- sharp and frequent mood changes;
- Attacks of apathy and indifference;
- inclination to antisocial behavior.
As you grow up, Klinefelter's syndrome also progresses - the signs become more pronounced at the time of puberty:
- narrow shoulders in parallel with wide hips and underdeveloped muscles;
- insufficient growth of hair on the face and body;
- high growth in comparison with peers;
- enlargement of the mammary glands (gynecomastia);
- low libido ;
- effeminate growth of pubic hair;
- small testicles and penis (sometimes).
The more superfluous elements in the karyotype, the more severely manifested Klinefelter syndrome. In boys with 2-3 duplicate chromosomes in the 23 pair there are additional symptoms:
- deformation of the chest;
- congenital heart defects ;
- ptosis of the eyelids;
- strabismus ;
- strong sweating of feet and palms;
- mental retardation;
- manic-depressive conditions;
- low IQ;
- deformation of the auricles;
- aggressive behavior;
- a wide and flat nose with an upturned tip;
- big mouth;
- far apart eyes;
- the presence of malignant neoplasms;
- headaches and attacks of hypertension;
- epilepsy ;
- propensity to addiction, alcoholism, homosexuality.
Klinefelter's syndrome - diagnostic methods
A standard 2-stage study helps to identify the pathology under consideration in the prenatal period of fetal development. Both phases are important if Klinefelter's syndrome is suspected - the diagnosis should include invasive and non-invasive methods. More often, this disease remains unnoticed before puberty, so it is found already in adolescence or adulthood.
Klinefelter's syndrome - prenatal diagnosis
The first stage of the study involves the analysis of the venous blood of the future mother, who is at the 11-13 week of gestation. If the abnormal content of chorionic gonadotropin and plasma protein A is present in the biological fluid, the woman is included in the group of pregnant women with the risk of having a sick child. At later periods, amniotic tissue or water is analyzed (invasive diagnostic methods):
- amniocentesis ;
Such techniques allow, with an accuracy of 99.8%, to refute or confirm Klinefelter's syndrome - a mosaic form that often flows secretly, is also determined by the listed methods. Invasive studies are based on a detailed interpretation of the karyotype of cells from the obtained biological samples, so they are as reliable and reliable as possible.
Klinefelter's syndrome - tests
Postnatal diagnosis is carried out by the appointment of a geneticist, endocrinologist or andrologist. Klinefelter's disease helps identify the following techniques:
- A smear from the mucous membrane of the mouth;
- blood test (biochemical, hormonal);
- Ultrasound of the scrotum;
- testicular biopsy;
- study of drawing on fingers;
How to treat Klinefelter's syndrome?
Completely eliminate the presented gene anomaly is impossible, therefore therapy is aimed at mitigating its manifestations. People have to constantly stop Klinefelter's syndrome - the treatment requires lifelong use of male sex hormones, beginning with the puberty period (11-12 years). Internal reception or injections of testosterone promote the normalization of the development of the reproductive system and its functioning.
Additional ways to treat Klinefelter's syndrome are needed to alleviate the attendant problems that provoke the described disease. These include:
- infection prevention;
- physical education;
- counseling therapist and speech therapist;
- stabilization of weight;
- mastectomy (if necessary);
- adherence to a balanced diet.
Klinefelter's syndrome - prognosis
This pathology is not fatal, with timely and adequate therapy, the risk of complications is minimal. Proper treatment significantly improves the prognosis if Klinefelter's syndrome is detected - the life expectancy of men with this chromosomal anomaly is the same as in healthy people. With the use of additional methods of therapy, patients are perfectly adapted in the society and fully able to work. Children with Klinefelter's syndrome can develop similarly to healthy peers, the main thing is to start using testosterone in time.
The latest achievements in the field of reproductive medicine help to solve even the problem of infertility. The method of in vitro fertilization using the ICSI procedure (intracytoplasmic sperm injection) has already been tested on patients with the described pathology. The test results are positive - absolutely healthy offspring are born.
Klinefelter's syndrome - prevention
Due to the lack of accurate data on the causes of the development of a genetic mutation, there are as yet no effective measures to prevent it. Harry Klinefelter's syndrome can not be prevented at the stage of pregnancy planning. The only necessary procedure is prenatal diagnosis. If a child is diagnosed with this disease, it is important to prevent complications. An effective way to treat Klinefelter's syndrome is hormones, which you have to use constantly.