Klinefelter syndrome - causes and symptoms

Klinefelter syndrome, 47, XXY is a clinical example of sex chromosome lesions.

Klinefelter disease is characterized by the presence of at least one extra X chromosome in boys, which leads to impaired puberty in them. It was clinically described for the first time by Kleinfelter in 1942. The population frequency is 1: 1000 males. Klinefelter syndrome occurs in about 1/800 live-born boys. The child gets the extra X chromosome from the mother in 60% of cases.

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What causes Klinefelter disease?

In most cases, the incorrect divergence of sex chromosomes occurs in the gametes of the parents. There are also mosaic variants, for example 47, XXY / 46, XY.

Klinefelter syndrome is caused by chromosomal abnormality, presented in the most typical form as 47XXU. Much less common mosaic forms - 46HU / 47HHU. As casuistic variants of the karyotype, forms 48ХХХУ, 47ХХУ / 46ХХ, 47ХХУ / 45ХО are described. There is also the observation of a patient with a karyotype 47ХХУУ46ХХ / 45ХО. The reason for these chromosomal abnormalities — the extra X chromosome in the male karyotype — may be the non-divergence of the X chromosome during the first or second meiotic division or the disruption of the mitotic discrepancy of chromosomes during the development of zygotes (mosaic variants). The method of DNA analysis revealed that 53% of patients with Klinefelter syndrome had an additional chromosome of paternal origin, which was the result of nondisjunction during the first meiotic division. 43% of patients had an extra chromosome of maternal origin as a result of the pathology of the first and second meiotic division. Apparently, there are no differences in the phenotype in patients who have an additional maternal or paternal X chromosome. The frequency of birth of boys with Klinefelter syndrome increases with increasing age of the mother. No similar dependence on the father's age has been identified. The presence of an extra X chromosome in the male karyotype does not affect the differentiation of the testicles and the formation of male genitalia. However, the vital activity of germinative cells is disturbed, spermatogenesis is absent. The reason for this is the activity of an extra X chromosome in germinative cells that normally have a haploid set of chromosomes. It was shown that in germinal cells of the ovary of the fetus in girls, before entering into meiosis, the second X chromosome is reactivated (normally only one is activated). In boys with the XXY karyotype, the pre-meiotic process of reactivation of the second X chromosome is also preserved; however, the discrepancy process is disrupted, and the germinative cell may contain two active X chromosomes, which leads to its death in the first days after the X chromosome is reactivated. In adult males with Klinefelter syndrome, when analyzing sperm cells, single, intact germinal cells had only a normal haploid chromosome set.

Symptoms of Klinefelter syndrome

At birth, Klinefelter syndrome is not clinically manifested. There are quite a lot of clinical options related to abnormalities of sexual status and somatic disorders in Klinefelter syndrome. The general regularity of the effect of the karyotype on the phenotype has not been identified, but patients with a mosaic karyotype with a normal male clone 47XXU / 46XU have less severe disorders.

The first distinct phenotypic signs of the disease appear in the pre- and pubertal periods of ontogenesis. Before puberty, boys can detect cryptorchidism (usually bilateral) and small penis size. 50% of boys have moderate mental retardation, accompanied by behavioral disorders, difficulties in contact with peers. Boys usually have a body length above the average age. Characterized by relatively long limbs, excess fat deposition of the female type (eunuchoid body type).

Late secondary signs appear. The most characteristic symptom of Klinefelter syndrome is hypoplasia of the testes and the penis (hypogonadism and hypogenitalism). In 50% of patients in puberty, gynecomastia is detected. There is a shallow decline in intelligence, which affects school performance. Adult patients are prone to alcoholism, drug addiction, homosexuality and antisocial behavior, especially under stress.

Puberty usually begins at a normal age, but often hair growth on the face is low. Such children have a predisposition to learning disorders, many have reduced verbal intelligence, impaired auditory perception and information processing, as well as reading skills. Clinical variability is significant, many boys and men with karyotype 47, XXY have normal appearance and normal intelligence.

At pubertal age, secondary body hair appears in the usual periods, there is also an increase in the penis. However, the volume of the testicles increases slightly, not exceeding, as a rule, 8 ml, the testicles have a dense consistency. Pubertal gynecomastia, often quite early, is detected in 40-50% of boys. In the future, these patients are at increased risk of developing breast carcinoma. Bone maturation usually corresponds to the age at the time of pubertal initiation, but later the differentiation of the skeleton bones is delayed due to insufficient testosterone secretion. Linear growth of limbs lasts up to 18–20 years, which leads to the formation of eunuchoid body proportions, the final growth of patients, as a rule, is higher than the growth of parents. Post-pubertal involution of the testicles leads to hypogonadism and loss of fertility. Histological examination revealed hyalinosis of the seminiferous tubules and the absence of spermatogenesis. The number of Leydig cells may be normal, but with age they undergo atrophy.

In addition to the symptoms of impaired sexual development in patients with Klinefelter syndrome, a number of congenital anomalies of bone tissue can be detected: clinodactyly, sternum deformity, cubitus valgus, coxa valga, hypertension, micrognathia, “gothic” palate, etc. Often the disease is accompanied by congenital heart disease. system. In patients, malignant neoplasms are quite often detected, in particular, there is information about a high frequency of germ cell tumors.

Mosaicism is observed in 15% of cases. These men can have children. Some men can have 3,4 and even 5 X chromosomes together with one Y chromosome. With an increase in the number of X chromosomes, the severity of mental retardation and malformations increases.


Klinefelter syndrome - what is it

The chromosome set of a healthy person consists of 46 chromosomes (23 pairs), all pairs of which are called somatic, except for the last one - sex. On these chromosomes lies the task of determining whether a boy or a girl will be born. Women have XX chromosomes, men - XY. The normal male genotype is as follows: 46 XY, which means the presence of X, Y chromosomes in one copy. When the XXY chromosome genotype occurs, the patient has xxy syndrome.

Klinefelter syndrome - karyotype

Violation of puberty in people with extra chromosome can not manifest itself outwardly, as seen in the photo. The karyotype of a man with Klinefelter syndrome has a direct effect on the manifestation of symptoms of the disease. The level of physical and mental abnormality depends on how many extra X chromosomes are in the genotype. Among adult patients, a tendency to drugs and alcohol is found, it is difficult for adolescents to communicate with their peers. Types of polysomies in males for chromosomes X and Y:

Congenital defects of appearance

Initial backwardness

Retardation manifests itself in severe form

Calm borders on aggression

Possible continuation of the kind

All symptoms are mild

Klinefelter syndrome - causes

The main cause of Klinefelter syndrome is a genetic mutation with a doubling of the female sex chromosome in the male genotype, which occurs when the zygote division is disturbed and in the process of meiosis. To determine the exact cause of the syndrome, diagnosis is necessary. Among the causes of such anomalies are considered:

  • environmental problems,
  • incest,
  • impaired immune system
  • viral infections
  • inheritance of the disease
  • too young or elderly mom.

Klinefelter syndrome - symptoms

Doctors identified characteristic symptoms of Klinefelter syndrome, which can be recognized if you look at the photo. Among the psychological signs of a genetic disease, slight deviations from normal behavior stand outwardly. For example, excessive cheerfulness, aggressiveness, restlessness in behavior. Such children, and later mature men, find it difficult to converge with other people. Symptoms of the syndrome often manifest after puberty:

  1. High growth. Peak growth increases from 5 to 8 years.
  2. Disturbed body proportions. Long legs, arm span exceeds height, high waist.
  3. Breast augmentation (gynecomastia). Eliminate will help gynecomastia bilateral.
  4. Testicular hypoplasia, which leads to androgen deficiency. Accompanied by a decrease in libido, impotence, small penis, small size of testicles (volume of testicles).
  5. Azoospermia, hypogonadism and cryptorchidism (absence of one or two testicles in the scrotum).
  6. Astigmatism, nystagmus, ptosis of the eyelid, squint.
  7. Hair coat on the female type.
  8. Anomalies of the skeleton, bone tissue: clinodactyly, chest deformity, osteoporosis.
  9. Infertility, sexual dysfunction.
  10. Malocclusion
  11. Congenital heart defects.
  12. The predominance of vagotonic reactions: bradycardia, acrocyanosis, sweating of the palms and feet.

Klinefelter syndrome - diagnosis

Reliable diagnosis of Klinefelter syndrome occurs by studying the chromosome set - karyotyping. Patients increased two indicators - luteinizing and follicle-stimulating hormone. In adolescents, male hormones will be reduced, and sexual characteristics characteristic of women will begin to manifest themselves. It is possible to make a diagnosis when the fetus is still in the womb, using amniocentesis, chorionic biopsy (fetal tissue sampling). For accurate diagnosis in other age is carried out:

  • blood chemistry,
  • Ultrasound of the heart,
  • densitometry (bone density),
  • obesity assessment
  • spermogram.

Klinefelter syndrome - treatment

It is impossible to recover from the disease, but life-long replacement therapy is needed, which includes intramuscular injections of the drug Sustanon-250, testosterone propionate, methyltestosterone. When you start treating Klinefelter syndrome with the help of sex hormone therapy, you can eliminate the risk of testicular atrophy and the development of secondary sexual characteristics. Psychotherapy will help to avoid social unsuitability. Children are shown hardening, visiting a speech therapist in order to correct speech disorders, prevent infectious diseases, exercise therapy.

Klinefelter syndrome - life expectancy

If therapeutic treatment is started in time, then life expectancy in Klinefelter syndrome will be the same as in healthy people. You can remove the external manifestations of the syndrome, such as in the photo, to improve life. The syndrome itself is not a factor in life shortening, but its concomitant symptoms can do this. Chronic diseases can be the cause of early death. It is necessary to consult a professional endocrinologist for the correct prescription of drugs.

Clinical manifestations

Klinefelter syndrome is an extremely common pathology and occurs in the male population with a frequency of 0.2%. Thus, for every 500 newborn boys, there is 1 child with this pathology (for comparison: congenital dysfunction of the adrenal cortex - 1 case per 10-25 thousand newborns). Klinefelter syndrome is not only the most common form of male hypogonadism, infertility, erectile dysfunction, gynecomastia, but also one of the most common endocrine pathologies, ranking third after diabetes and thyroid disease. However, there is reason to believe that approximately half of the patients throughout the life of this syndrome remain unrecognized and such patients can be observed in doctors of various specialties with complications associated with the lack of therapy of the underlying disease, that is, the manifestations and consequences of hypogonadism. Violation of the number of chromosomes is due to their nondisjunction, either when dividing meiosis at an early stage of germ cell development or during mitotic cell division at the initial stages of embryo development. The pathology of meiosis prevails, in 2/3 of cases, nondisjunction occurs during maternal ovogenesis and in 1/3 - during paternal spermatogenesis. The risk factor for Klinefelter syndrome is, apparently, the age of the mother, the relationship with the age of the father has not been established. Unlike many other aneuploidy, Klinefelter syndrome does not increase the risk of miscarriage and is not a lethal factor.

Clinical manifestations General information

Klinefelter syndrome is a disomy or polysomy on the female sex chromosome, in which males have at least two X chromosomes and one Y chromosome. Klinefelter syndrome occurs with a frequency of 1 case per 850-1000 newborn boys. Among children suffering from oligophrenia, the prevalence of Klinefelter syndrome is 1–2%. The syndrome was named after the American doctor Harry Klinefelter, who first described it in 1942. The karyotype of such patients with an extra X chromosome was determined in 1959. Since the leading clinical manifestation of Klinefelter syndrome is primary hypogonadism, these patients are administered by endocrinology and andrology.

Causes of Klinefelter Syndrome

As in the case of Down syndrome, chromosomal aberration in Klinefelter syndrome is associated with nondisjunction of chromosomes (in the latter case, sex) in the process of meiosis or impaired division of the zygote. In this case, significantly more often (in 60%) boys with Klinefelter syndrome receive an excess maternal X chromosome than their father's.

Among the possible causes of this kind of chromosomal abnormalities are viral infections, late pregnancy, the inadequacy of the regulatory mechanisms of the maternal and paternal immune systems.

In the presence of an extra X chromosome, aplasia of the epithelium of the testes develops, their subsequent hyalinization and atrophy, which in adulthood is accompanied by azoospermia and endocrine sterility. Among the causes of male infertility, Klinefelter syndrome is 10%, which should always be remembered by experts in the field of reproductive medicine.

The most common cytogenetic type is the full version of Klinefelter syndrome with karyotype 47, XXY. Mosaicism is less common (46XY / 47XXY, 46XX / 47XXY), even less often - polysomy 48, XXXY, 48, XXYY, 49, XXXXY, etc.In the mosaic variant (about 10% of cases), a part of the cells has a normal karyotype, so men with Klinefelter syndrome may have normally developed and functioning sex glands and intact reproductive abilities.

Diagnosis of Klinefelter syndrome

Like other chromosomal abnormalities, Klinefelter syndrome in the fetus can be detected even at the stage of pregnancy during invasive prenatal diagnosis (amnioceteza, chorionic biopsy or cordocentesis with subsequent analysis of the karyotype or CP-PCR).

Postnatal diagnosis of Klinefelter syndrome is carried out by endocrinologists, andrologists and geneticists. In the study of sex chromatin in the cells of the mucous membrane of the oral cavity Bar's bodies are present, which is a marker of Klinefelter syndrome. Other characteristic signs are special changes in the skin pattern on the fingers. However, the final diagnosis of a chromosomal abnormality can be established only after a study of the karyotype.

Ultrasound of the scrotum reveals a decrease in testicular volume. In the study of the androgen profile, the level of testosterone in the blood of patients with Klinefelter syndrome is lowered, however, there is an increase in the level of follicle-stimulating and luteinizing hormones. In the analysis of sperm revealed oligo - or azoospermia. A morphological study of material obtained by testicular biopsy reveals hyalinosis of the seminiferous tubules, hyperplasia of Leydig cells, a decrease in the number of Sertoli cells, and the absence of spermatogenesis.

During the life of a man with Klinefelter's syndrome, they may contact an andrologist, a sexologist, an endocrinologist with problems of infertility, impotence, gynecomastia, osteoporosis, etc., however, often the underlying disease remains unrecognized.

Treatment for Klinefelter syndrome

Fully cured of Klinefelter syndrome is not possible. However, all patients need symptomatic and pathogenetic therapy. In childhood, prevention of infectious diseases, hardening, exercise therapy, correction of speech disorders with the help of a speech therapist are necessary.

From adolescence, patients with Klinefelter syndrome are given lifelong sex hormone replacement therapy (intramuscular injections of testosterone-propionate, Sustanon-250, sublingual methyltestosterone, etc.). Early and adequate hormone therapy prevents atrophy of the testes, contributes to increased sexual desire, the development of secondary sexual characteristics. With a pronounced increase in the mammary glands, an operation is carried out to correct the gynecomastia.

In order to increase working capacity and social adaptation, prevent psychopathisation of the personality and its asocial orientation, psychotherapy is shown.

Prognosis and prevention of Klinefelter syndrome

Patients with Klinefelter syndrome have a normal life expectancy, but the propensity to develop chronic diseases can be a risk factor for early mortality. Most patients with Klinefelter syndrome are infertile, the only possible option for having children in families where the partner is sick is the use of donor sperm. However, with the mosaic form of Klinefelter syndrome, men can become fathers on their own or using assisted reproductive technologies (IVF).

To assess the likelihood of having a baby with Klinefelter syndrome in the course of pregnancy, women are offered prenatal screening. However, even in the case of obtaining positive data for the presence of Klinefelter syndrome in the fetus, insisting on termination of pregnancy by an obstetrician-gynecologist is unacceptable. The decision on whether to prolong pregnancy should be taken by parents. With a normal karyotype of parents, the risk of re-emergence of a child with the same chromosomal abnormality is no more than 1%.

Clinical supervision of patients with Klinefelter syndrome is performed by an endocrinologist.

What is Klinefelter Syndrome?

Over the past century, scientists have described a huge number of genetic diseases caused by mutations at the gene level. Many of them are extremely rare, but there are those whose frequency in the population is quite high, for example, the pathology of sex chromosomes.

One of these pathologies is Klinefelter syndrome. This genetic disease occurs only in men and according to statistics, it is recorded in one newborn boy out of 700.

For the first time the syndrome was described in 1942 by a doctor from the United States, Harry Kleinfelter. In the 70s, American scientists conducted active pathology studies through the study of chromosomal sets (karyotypes) of all newborn boys. What is Klinefelter syndrome, what are its symptoms, is it amenable to diagnosis and treatment - these and other issues will be discussed in our article.

Cytogenetic explanation and causes

There are two versions of when exactly Klinefelter syndrome was explained from a genetic point of view. The first one states that the cytogenetic basis of the disease was first described by scientists in Brig and Bar in 1956. The second one attributes the discovery to Jacobs and Strong in 1959.

The chromosome set of a healthy person consists of 46 chromosomes (23 pairs). 44 chromosomes are somatic, and the remaining 23rd couple - sex. They determine the identity of the female or male. In the karyotype of a woman, there are two X chromosomes, and in a man, X and Y chromosomes.

The genetic essence of Klinefelter syndrome is that instead of the normal male genotype with one X chromosome and one Y chromosome (46, XY), the patient will have one (or more) extra sex chromosome X. The genotype of such a man will be (47, XXY). This change in chromosome set leads to certain defects in appearance, health problems, and even mental retardation. If we consider this aspect as a type of inheritance, then, due to DNA analysis, it became known that in most cases (about 67%) Klinefelter syndrome occurs due to violations of the division process (meiosis) during the formation of female reproductive cells.

The exact causes of the disease to date have not been established. Most researchers deny the effect of heredity, since infertility is almost always observed in men with this disease. However, scientists note risk factors that may contribute to the development of pathology: too young or, on the contrary, very mature age of the mother, unfavorable environmental situation, marriage between blood relatives.

Diagnosis of the disease

In many cases, Klinefelter syndrome remains unrecognized. People with this pathology turn to the help of doctors in adulthood about such problems as impaired erectile function, infertility, osteoporosis, and an increase in the mammary glands. They do not diagnose Klinefelter syndrome.

It is possible to reliably establish that a man has Klinefelter syndrome using karyotyping, that is, studying a set of chromosomes. It is strongly recommended to carry out karyotyping in children who, in addition to signs of the syndrome, have a mental retardation.

For the purpose of diagnosis, a biochemical blood test is also used to determine the content of male sex hormones in a patient. Up to 10–12 years old, boys with Klinefelter’s syndrome have hormone levels that stimulate the activity of the reproductive system, within the regulatory limits. The concentration of testosterone in older patients may be normal or slightly reduced, but the content of FSH (follicostimulating) and LH (luteinizing) hormones will be higher than normal.

Due to the fact that a teenager with Klinefelter syndrome suffers from a reduced level of male sex hormones with an increased number of female, he has secondary female sex characteristics: low voice timbre, breast enlargement, etc.

A number of additional methods are also used to establish the diagnosis of Klinefelter syndrome:

  • densitometry (determination of bone density),
  • spermogram (determination of sperm activity in seminal fluid),
  • assessment of the severity of obesity,
  • Ultrasound of the heart,

Pregnancy with a fetus with an extra X chromosome, as a rule, passes without any problems. However, it is possible to establish the diagnosis of Klinefelter syndrome in the prenatal period, when the fetus is in the womb. Such an early determination of abnormalities is possible due to the methods of invasive prenatal diagnosis: chorionic biopsy and amniocentesis. Each of them can detect genetic abnormalities with an accuracy of more than 99%.

Both studies imply surgery to collect a sample of fetal tissue. DNA material of the unborn child is extracted from this sample, which is studied in the laboratory for the presence of chromosomal abnormalities.

48XXYYOne additional chromosome X and YDual X chromosomesThe frequency of manifestation - rare, in the form of three additional X-chromosomes
46 XY / 47XXUThe mosaic form may contain both normal sex cells and defective

It is carried out in the period from 9.5 to 12 weeks of pregnancy.

The procedure involves puncturing the abdominal wall of the mother with a special needle and collecting the chorionic villi from the developing placenta, since the placenta has the same genetic material as the fetus. The whole process takes place under the control of the ultrasound machine.

Held between 16 and 18 weeks of pregnancy.

During the procedure, an amniotic fluid (amniotic fluid) is taken for analysis, which contains the genetic information of the child. To collect the material, a special needle is passed into the uterus, controlling its movements on the screen using an ultrasound probe. In about one minute, 15 ml of amniotic fluid will be collected.

Chorion biopsy Amniocentesis

These diagnostic methods are physical and psychological discomfort for pregnant women. Approximately half of the patients feel pain cramping character. There is even a chance of miscarriage after these procedures, but it is extremely small - about 1%. Other possible complications include: infection, leakage of amniotic fluid, bleeding.

It is worth noting that these diagnostic methods, due to their insecurity, are prescribed by the doctor strictly if there are certain indications:

  • The age of the future mother is over 35 years old,
  • There was a high risk of chromosomal abnormalities in the fetus according to the results of screening during pregnancy,
  • There was already a pregnancy with chromosomal abnormalities in the fetus, ending in miscarriage,
  • In the family there is a child with chromosomal pathology,
  • Future parents are related.

Consequently, the future mother’s desire to undergo a highly accurate examination for the presence of Klinefelter syndrome and other genetic pathologies in the fetus will not be enough.

Fortunately, methods for prenatal diagnosis are constantly being improved, and there is a safe way to detect a large number of fetal pathologies already in early pregnancy. An example of the successful development of prenatal technologies is the non-invasive DNA test Panorama, developed in the USA in 2012 and having proved its effectiveness in many countries around the world, including Russia.

The test identifies fetal chromosomal abnormalities such as Down syndrome, Edwards and Patau syndromes, microdeletion syndromes, and sex chromosome abnormalities, which include Klinefelter syndrome. Not only women who have indications for invasive diagnostics can pass the test, but also all who wish to receive the most complete information about the future health of the future baby.

To study a pregnant woman, you just need to donate blood from a vein. Further, with the help of molecular technologies, the cells of the fetus are extracted from the material obtained, which will be carefully studied for the presence of genetic variations. The low risk result obtained as a result of the analysis shows that the probability that the child has pathologies that the test can reveal is almost zero. High risk is not a sentence, but requires further diagnosis, namely, invasive studies to confirm or deny the diagnosis.

The study has high accuracy (more than 99%) since the 9th week of pregnancy. The test is absolutely safe for both the mother and the fetus, and allows parents to find out the sex of the child.

Summarizing the issue of diagnosis of this disease, it should be noted that its early detection is extremely important. This will help prevent possible complications in the form of physical and mental abnormalities in the patient.

Symptoms and forms of the disease

If you look at the photos of children with Klinefelter's syndrome, then you will notice that at an early age there are no characteristic external manifestations of this pathology. The disease should be suspected if the boy has a retarded mental development, learning difficulties and some behavioral anomalies. A child with Klinefelter syndrome may be aggressive, restless, or, conversely, too cheerful. Also, these children have difficulty in establishing psychosocial contacts.

The closer the boy comes to puberty, the clearer are the classic external signs of the disease. The most prominent symptoms of Klinefelter syndrome in children and adolescents:

Children with Klinefelter syndrome are noticeably superior in the growth of their peers. A sharp increase in their growth occurs, as a rule, from five to eight years.

Disproportions in the body structure are noted, first of all, this is a high waist and limbs that are too long.

Due to the lack of androgens (steroid male sex hormones), many patients are characterized by a female-built body mass with excessive fat. Accompanied by this feature wide hips and narrow shoulders, like women.

This phenomenon, characterized by a painless, symmetric enlargement of the mammary glands in men due to glandular and fatty tissues, is observed in 50-70% of healthy adolescents. In rare cases, the condition is accompanied by painful sensations when palpating. Pubertal gynecomastia regresses independently, and its signs disappear without a trace within two years. However, if a person has Klinefelter syndrome, the involution of enlarged glands to the former state does not occur.

Violation of the structure of the genital organs

The size of the testicles in patients with the syndrome is small and not age-appropriate. This becomes especially clear at a transitional age, when their growth slows down very much or stops at all. The penis is also distinguished by its small size. In some cases, there is cryptorchidism (absence of one or two testicles in the scrotum). These changes lead to infertility in adulthood.

People with Klinefelter syndrome have some typical facial features for this disease: a wide eyed and a small degree of Mongoloid, deformed auricles, a large parted mouth, a wide and flat nose, some have a squint.

40% of adolescent boys with Klinefelter's syndrome have hair that is too rare on their face. Many have little underarm hair and female pubic hair growth.

Anomalies of bone tissue

In addition to disorders associated with sexual development, carriers of extra X - chromosomes suffer from congenital anomalies of bone tissue. They may experience deformity of the sternum, congenital defects of the fingers (clinodactyly), abnormal development of the jaw and nasopharynx ("Gothic" sky and micrognathia).Some of these defects can be eliminated with surgery.

Teenager with Klinefelter Syndrome

Mental and mental development

Approximately every second patient who has Klinefelter syndrome, suffers from a moderate mental retardation. As a result of this factor, difficulties often arise in attempts to establish contact with peers and behavioral disorders.

Observations suggest that in children and adolescents with Klinefelter syndrome, there is often a delay in speech development, problems with the auditory perception of the material. Decrease in verbal intelligence, violation of information processing processes, difficulty in acquiring reading skills lead to the fact that maintaining normal school performance becomes a real problem. In a more mature age, this flows into the inability to clearly express one’s thoughts. Also, adult patients have a tendency to alcoholism and drug use.

The karyotype of a man with Klinefelter syndrome affects the severity of certain symptoms of the disease. In other words, the number of extra X chromosomes in the genotype has a direct effect on the formation of mental and physical abnormalities.

(one extra X chromosome and Y chromosome)

(two extra X chromosomes)

(three extra X chromosomes, the rarest form)

(mosaic form, which is characterized by the presence of both defective and normal germ cells)

KaryotypeFeatures of the patient
  • Tall (from 185 cm),
  • Reduced intelligence, slow speech,
  • Frequent depressions
  • Increased aggression
  • Social adaptation is difficult
  • Medium or tall,
  • Congenital malformations (adhesions of the bones, flattened bridge of the nose, wide-fitting eyes, etc.),
  • Intellect can range from moderate to mild forms of mental retardation,
  • Tendency to apathy, infantilism, lack of aggression.
  • Short stature
  • Congenital malformations: heart disease, cleft lip, joint deformity, small testicle size, penis),
  • Mild to severe mental retardation
  • With general calm and friendliness capable of outbreaks of aggression.
  • In comparison with the classical form, there are mild symptoms,
  • There is an opportunity to produce offspring.

It can be noted that an increase in the number of X chromosomes in the genotype contributes to an increase in the severity of developmental defects and abnormalities in mental development. For example, carriers of karyotype 43 XXXXY have such an impressive set of symptoms that it is possible to detect the presence of the syndrome at an early age.

Mosaicism is found only in 15% of cases of pathology. Most men with a karyotype 47 XXY, do not have any obvious defects of appearance and are characterized by normal development of intelligence.

Life with Klinefelter syndrome

The prevalence of the syndrome takes a rather impressive position - the third place among the whole range of endocrine diseases. Only diabetes mellitus and thyroid pathology are ahead of it.

The life expectancy of men affected by this gene mutation is, in total, the same as that of healthy people. However, it is worth noting that in many cases their life path is accompanied by health problems that can lead to early death.

Complications that may result from this disease:

  • mental developmental problems that may develop to the debilityal stage,
  • mental disorders leading to alcoholism, suicidal feelings, antisocial lifestyle,
  • high risk of diabetes, obesity,
  • aggravation of congenital heart defects,
  • osteoporosis (bone fragility),
  • the probability of occurrence of malignant tumors, for example, breast carcinoma, provoked by gynecomastia,

One of the main problems of Klinefelter syndrome is infertility. The loss of fertility is due to abnormalities of the genital organs and the absence of viable spermatozoa in the seminal fluid. Today, an active search is underway to find a solution to this problem, including through IVF (in vitro fertilization), but for these patients, this technique is under development and is not widely used.

In general, the prognosis for patients with Klinefelter syndrome is favorable. Patients are quite well adapted to life. The severity of complications caused by the syndrome depends on how early the chromosomal abnormality was diagnosed and how soon the treatment was started. The sooner this happens, the fewer the complications.

Treatment and Prevention

There are no special preventive measures for Klinefelter syndrome. A genetics consultation is worth taking if there are cases of hereditary diseases in previous generations or there are other risk factors.

It is impossible to completely cure the syndrome today, however, continuous therapy can greatly facilitate the lives of patients. The syndrome is treated by means of substitution therapy, which involves taking drugs that increase the concentration of testosterone. The therapeutic course helps to improve the appearance and well-being of the patient, as well as restores the ability of a man to lead a normal sex life. Competent therapy can prevent the development of osteoporosis and muscle weakness.

In order to prevent gynecomastia, treatment should begin at a young age, as soon as Klinefelter syndrome has been diagnosed. In adulthood, gynecomastia develops to such a state that it cannot be treated. Enlarged breasts are often the cause of psychological complexes in patients, in which case you can resort to the removal of the mammary glands (mastectomy).

Experts recommend that patients monitor their diet and do not gain excess weight, so as not to provoke obesity and type 2 diabetes.

Watch the video: What is Turner Syndrome? Animated Explanation Video (January 2020).