Prader-Willi syndrome: description, diagnosis, photo, treatment. Prader-Willi syndrome: causes, manifestations, diagnosis, treatment, prognosis Recent advances in the treatment of Prader-Willi syndrome

Prader-Willi syndrome is a hereditary genetic disorder that occurs due to the absence of a paternal copy or disomy of a section of chromosome 15. Karyotype 46 XX or XY, 15q-11-13. The anomaly was discovered in 1956 by Prader, Willy, Ziegler, Fanconi and Labhart. There is another similar disease - Angelman syndrome, but in this case maternal genes are affected. Both disorders are incurable.

Causes of the syndrome

The disease develops due to a disruption in the normal functioning of the q11-13 section of the 15th pair of chromosomes. PWS can occur due to damage to only the paternal chromosome.

The reasons for the development of the disease include:

• Loss of region q11-13 of the father's gamete. It occurs in about 70% of people.
• Absence of a copy of chromosome 15 of the father and disomia of the mother's chromosomes. It is observed in 20% of cases.
• In 5% of cases, deactivation occurs in the fetus due to methylation of the paternal chromosome at q11-13.

Due to the fact that with Prader-Willi syndrome, the paternal chromosome is damaged and all its work is disrupted, there is an increased deposition in the subcutaneous fat. The exchange of sex hormones is also difficult, which means that the healthy functioning of the genital organs becomes impossible, various anomalies appear in the structure of the organs of the reproductive system.

Patients with PWS are predisposed to the formation of malignant tumors due to genetically inherent weak DNA protection.

Symptoms of Prader-Willi Syndrome

The presence of a violation can be detected already in the early stages of pregnancy. The fetus is not only inactive, but also incorrectly located, its asphyxia or malnutrition is possible. Sometimes there is polyhydramnios. Also in a pregnant woman, the level of gonadotropin changes. Children are often born prematurely, they are prone to breech presentation. Based on these indicators, specialists should conduct additional diagnostics.

In infancy, with Prader-Willi syndrome, the child has weakened muscle tone, impaired coordination of movements, and hip dislocation is common. Sometimes the baby does not have a sucking and swallowing reflex, so food is possible only through a probe. In rare cases, breathing is disturbed, artificial ventilation of the lungs becomes necessary.

Children with the syndrome regularly experience drowsiness, apathy, and fatigue. They are often stubborn, hostile and aggressive.

Already in infancy, skull dysmorphia and acromicria of the arms and legs become noticeable, which manifests itself:

1. strabismus;
2. Almond shaped eyes;
3. Large bridge of nose;
4. Elongated shape of the skull;
5. Small mouth or narrow upper lip
6. Violation of pigmentation of the iris of the eyes, skin and hair;
7. Ears low.

As the disease progresses, a person experiences:

• Diseases of the spine: scoliosis and osteochondrosis;
• Increased appetite, and therefore overweight;
• Diseases of the oral cavity: caries, gingivitis;
• Lag in mental development;
• Ataxia;
• Muscle spasms;
• late reproductive maturity.

limb changes in PWS

Already in adolescence, children with the Prader-Willi symptom do not look like their peers. Patients are characterized by:

1. Short stature and overweight;
2. Lag in speech development;
3. Too much flexibility
4. Learning disability.

In children with PWS, the developmental coefficient does not exceed 80 units, while the norm is 85-115 units. However, they have a highly developed imagination, the guys know how to write and read, but due to the small set of words they own, their speech abilities still lag behind the norm. Mathematics and calligraphy are difficult.

The mental state of patients is usually unstable. Regular outbursts of aggression, anger and hysteria are replaced by friendliness. Such children are characterized by obsessive-compulsive disorder, hallucinations, depression, sometimes dermatilomania occurs - peeling off the skin on the body.

Patients suffer from a malfunction of the hypothalamus. As a result, underdevelopment of the ovaries and testicles appears, and, consequently, the production of hormones is disrupted. It also leads to insufficient pigmentation of the skin, eyes and hair. The child has an endless feeling of hunger, obesity begins. The deposition of fat usually occurs in the thighs and abdomen.

PPV diagnostics

Diagnosis of the disease in its initial stages can prevent the development of some of its symptoms:

• Therapy, started at an early stage, develops the correct eating behavior in the child;
• If before the 18th month of life, experts began to adjust the ratio of growth hormones, the baby's physique will develop correctly, like in a healthy person.

Usually the diagnosis is made on the basis of external and internal symptoms. In infants, the disease is assumed at 5 points scored on a special scale, in children older than 3 years - at 8 (4 of them should be major signs).

Large signs equal to one point:

• Periodic difficulties with feeding a newborn;
• Delay in cognitive development up to 5-6 years;
• Special facial features: almond-shaped eyes, small mouth, narrow upper lip;
• Muscle hypotonia, detected at the age of 1 to 3 years;
• Changes in the structure of the organs of the reproductive system;
• Development of obesity.

Minor signs (0.5 points):

• Insufficient activity of the fetus;
• Refractive anomalies;
• Damage to the skin;
• Reduced pigmentation of the iris, hair and skin;
• thick saliva;
• Short stature;
• Disproportionate limbs;
• sleep problems;
• Mental deviations in behavior;
• Articulation disorder.

In addition to the above criteria, to accurately determine the diagnosis, karyotyping should be performed and the presence of various modifications at the level of chromosome 15 should be determined. DNA markers and the method of prometaphase analysis are also used.

Often, the pathology becomes noticeable already during an ultrasound examination of pregnancy. The specialist notices an increase in amniotic fluid, fetal hypoxia, or its non-standard location. At the slightest suspicion of a violation, the expectant mother will have to undergo perinatal diagnostics, including genetic testing and a blood test for gonadotropin levels. Also, to determine the syndrome, it is necessary to use special molecular genetic markers.

Children with PWS move little, often steal food, hide food, and, despite a recent snack, are constantly hungry. In this case, there is a threat of apnea - stopping breathing during sleep, dangerous with a possible fatal outcome.

PWS treatment

Unfortunately, even in the 21st century, the disease is not treatable. Specialists can only alleviate the patient's course of the disease. For example, if an infant has trouble breathing, doctors put him on a ventilator. In case of violation of swallowing, the patient is prescribed enteral nutrition through a special probe. With reduced muscle tone, therapeutic massage or physiotherapy is necessary.

In rare cases, patients need a psychiatrist. Psychological help is especially needed for children with a lag in psycho-emotional development and speech.

You should also regularly replace chorionic gonadotropin. To stimulate timely sexual development, you need to take hormonal drugs, and boys also need to bring down the testicles.

Children with this syndrome need to regularly inject somatotropin. It will save a person from a constant feeling of hunger, which means it will prevent the appearance of obesity and help increase muscle mass gain. But in any case, the child's appetite must be monitored by parents, and sometimes by a nutritionist.

Adults around the baby need to understand that his health directly depends on nutrition. And if even at preschool age you can practically not limit the child's diet, then already in primary school it is necessary to provide a low-fat diet, the calorie content of which should not exceed daily spending. During the period of active treatment with identified obesity - up to 1000 kcal.

It is advisable to hide all products from the child, or close the refrigerator with a lock. Children with Prader-Willi syndrome should move a lot, play a variety of sports and go out for evening walks as often as possible. They need to be registered with a neurologist and an endocrinologist.

Needs of people with PWS

Any person sooner or later needs medical care, treatment of various diseases and strengthening of their immunity and health in general. Patients with Prader-Willi syndrome are no exception. But often patients encounter the following barriers to health:

1. Difficulties in communicating and understanding with others;
2. Insufficient mobility due to obesity;
3. mental disorders;
4. Little knowledge of society about the disease;
5. Lack of special schools for children with PWS.

Complications

Prader-Willi syndrome itself is usually not life threatening. Timely therapy helps people live to at least 60 years. But if treatment is missing or incorrectly prescribed, the following complications may appear:

• Heart failure;
• Diabetes;
• Diseases of the spine;
• Malignant tumors, incl. leukemia;
• Diseases of the respiratory organs and the nervous system, (breathing during sleep is especially dangerous);
• Cartilage destruction due to excess weight.

Prevention

It is impossible to prevent a congenital disease, the main thing in this case is to prevent the occurrence of complications. Treatment of the syndrome should begin as early as possible, then it will be easier for the child to adapt to school and life in society.

Prevention of the disease can include medical genetic counseling of families who have a predisposition to the onset of the syndrome. Future parents need to conduct prenatal genetic testing, which will help determine the structural features of the fetus's chromosomes.

To improve the life of a child with PWS, it is necessary to ensure the constant cooperation of medical specialists, parents and the baby himself.

Forecast

Most often, the prognosis is directly determined by the presence of diseases of the heart, respiratory organs, kidneys and the state of the endocrine system. According to the established statistics, the life expectancy of people with Prader-Willi syndrome who have not been sufficiently actively treated is about 30 years. But there are also many cases when people lived 50-60 years. The main thing is to be registered with a doctor, follow his instructions, regularly undergo all the necessary studies.

Video: a child with Prader-Willi syndrome

It is considered a very rare genetic disorder in which seven genes located on the 15th paternal chromosome are completely or partially absent and do not function normally.

This genetic pathology occurs due to the fact that only the copy of a certain gene received from the father functions correctly. There are also some irregularities in the copy from the mother. Let's consider in more detail.

In the body of a healthy person, there are copies of genes, thanks to which the organs can function without any deviations from the norm. With the development of Prader-Willi syndrome, such copies are absent. Currently known diseases that are inherently similar to this disease.

A similar mechanism of occurrence can also be observed in Angelman syndrome, but even in this case, mutations affect the genetic material received from the mother. Such diseases, as a rule, manifest themselves in various forms and have varying degrees of severity. However, they are incurable.

Causes of the syndrome

Prader-Willi syndrome is a hereditary deterministic pathology that develops only with the development of certain anomalies. In other words, with certain chromosomal disorders, parental genes begin to suffer, which leads to serious changes. The clinical picture develops when seven genes in the 15th paternal are absent or not expressed. In this case, the embedded information in DNA is not converted into RNA.

Scientists who were engaged in finding out the causes of this hereditary pathology previously believed that a homozygote is formed due to such a deviation. Then it was concluded that the predominant traits are present in autosomes, and the main way of transmission of the disease is inheritance.

Geneticists carried out numerous pathologies, with the help of which it was found that the fathers of children affected by the disease had a translocation of chromosome 15. Photos of children with Prader-Willi syndrome are presented in our article.

genetic mechanism

To date, it has been precisely established that with this pathology, the 15th chromosome is damaged in segments from q11.2 to q13. The same thing happens with Angelman syndrome. However, this disease is characterized by completely different symptoms. Such a dissonance can only be explained by such a phenomenon in genetic science as genomic imprinting, as well as uniparental disomy.

In uniparental disomy, both chromosomes are inherited from only one parent, but for this to happen, certain biochemical factors must influence the gene material. This fact was established using prometaphase analyzes and DNA marking of some loci of this chromosome.

Prader-Willi syndrome is caused by two main mechanisms: microdeletion of the 15th chromosome, received from the father, and idiosomy of the maternal chromosomes, both of which are received from the mother.

With genomic imprinting, phenotypic changes depend on whose chromosomes - father or mother - have been expressed.

Prader-Willi syndrome in children

The mechanisms of disorders that occur in the body of a patient with a syndrome have not yet been fully studied. However, at the same time they have a number of symptoms inherent only to this type of disease. It is believed that patients gain weight due to an increase in the formation of fat cells and a decrease in the level of lipolysis.

In addition, there are dysfunctions of the hypothalamus, which are mainly noted in its two nuclei - ventrolateral and ventromedial. Such processes lead to failures in the formation of secondary sexual characteristics. Decreased tyronase activity in hair follicles and melanocytes results in hypopigmentation of the hair, skin, and iris.

What are the main symptoms of Prader-Willi syndrome?

Symptoms of the disease

This pathology can be detected even in the early stages of pregnancy with an incorrect location of the fetus and with its low mobility. In addition, the level of gonadotropin produced by chorion cells can change significantly in a pregnant woman, and symptoms of polyhydramnios may be present. Based on these symptoms, a diagnosis cannot be made, however, they may be a sufficient basis for further diagnosis.

Dysplasia

In children, Prader-Willi syndrome (pictured above) can be expressed in the presence of congenital dislocations of the hip (dysplasia), in a weakening of muscle tone, and also in coordination disorders. There are cases when a newborn could not suck and swallow breast milk on his own. In this violation, nutrition is carried out using a probe. Respiratory disturbances may occur, and in some cases mechanical ventilation of the respiratory system is required.

Drowsiness

In addition, there are other symptoms of Prader-Willi disease. For example, children may experience increased sleepiness. As for external factors, the child has developmental delays. Therefore, such patients are characterized by short stature, underdeveloped hands and feet, and strabismus often develops.

Other symptoms

In the future, this pathology is characterized by the following symptoms:

1. Curvature of the spinal column.
2. Caries of milk teeth and increased density of saliva.
3. Tendency to overeat.
4. Hypofunction of the gonads, which further lead to infertility.
5. Obesity.
6. Delayed motor and speech development.
7. Retardation in psychomotor development.
8. Delay in puberty.

These symptoms are determined visually. During adolescence, the following symptoms are detected:

Diagnosis of Prader-Willi syndrome

This hereditary pathology can be noticed even during fetal development during ultrasound. In such cases, women are recommended certain types of prenatal diagnosis, and if necessary, specialists use invasive methods to solve the problem.

After childbirth, an experienced specialist has the right to make a diagnosis of Prader-Willi disease already at the initial examination of the baby. However, specific genetic testing is needed to confirm it. The content of chorionic gonadotropin is also examined in the mother's blood. Thanks to such methods, it is possible to identify submicroscopic and functional pathologies at the DNA level.

What are the criteria for diagnosis?

The diagnosis can be made according to the following clinical criteria:

1. At birth, low weight and height of the child in cases of full-term pregnancy.
2. Incorrect position, including breech presentation of the fetus.
3. Other microanomalies in development.
4. Expressed system.
5. Reduced pigmentation of the skin and hair.
6. Obesity, developing, as a rule, by six months.
7. Delays in psychological, motor and speech development.

Children who have this syndrome constantly require food and move very little. Due to excessive weight gain, they may experience such a complication as sleep apnea, which is often the cause of death in their sleep.

What is the treatment for Prader-Willi syndrome?

Treatment

To date, there are no specific treatments for the syndrome. Therapy is usually symptomatic. If a newborn has problems with respiratory activity, then he is transferred to artificial lung ventilation, and in case of problems with swallowing, they are put through which enteral nutrition is carried out. In cases of decreased muscle tone, massage and a variety of physiotherapy methods are indicated.

Children with Prader-Willi disease are given daily recombinant growth hormone, which maintains muscle mass gain and helps reduce the patient's appetite. The replacement of chorionic gonadotropin is also carried out.

During such a disease, hypogonadism is observed, that is, underdevelopment of the gonads and a change in the functions of the reproductive system. In this case, hormone replacement therapy is carried out, which allows to stimulate growth and puberty.

In some cases, children with speech delays and mental retardation may need the help of a psychiatrist or psychologist. And most importantly, it is necessary to constantly monitor the amount of food that they consume. Children with Prader-Willi syndrome are prescribed special diet therapy.

The risk that the second child of a couple whose first child suffers from this disease will be born with the same genetic problems is incredibly high. In such a case, parents are advised to undergo a consultation, where specialists will comprehensively examine them and calculate the risks.

Children with Prader-Willi disease need constant monitoring by an endocrinologist and a neurologist.

Improvement in general well-being against the background of the disease

Among people who have the syndrome, somatic morbidity rates are significantly increased, communication is difficult, and there is a need for specific assistance due to the characteristics of their disease. They may not understand why it is necessary to take care of their health. If the condition is satisfactory and the patient feels well, his quality of life improves.

The following factors must be eliminated:

1. Increased risk of sudden death.
2. The likelihood of getting sick.
3. An increase in the number of factors that determine material well-being.
4. Insufficient access to wellness and health services.

People with Prader-Willi pathology have special needs due to their underlying condition. They need special treatment for acute and chronic pathologies, assistance in strengthening general health, etc. Their needs must be met in special institutions providing medical care, which, in turn, may consist in the treatment of the underlying disease and somatic disorders, associated with the underlying pathology.

What is the life expectancy with Prader-Willi Syndrome? This disease often leads to a decrease in the life expectancy of patients up to 60 years. However, the prognosis for the recovery of such people is very disappointing.

The article presented a detailed description of the Prader-Willi syndrome. Now you know what this pathology is.

Description:

Prader-Willi syndrome is a rare genetic anomaly. In Prader-Willi syndrome, approximately 7 genes from the 15th chromosome, inherited from the father, are absent or not expressed.

Karyotype 46 XX or XY, 15q-11-13. The disease was first described by Swiss pediatricians A. Prader and H. Willi in 1956.

According to the Prader-Willi Syndrome Association Registry, there were 1,595 patients in the United States and Canada as of December 1986. In recent years, it has been possible to establish a population frequency of pathology, which is 1: 10,000 - 1: 20,000.

Causes of Prader-Willi Syndrome:

The authors who first described the syndrome suggested an autosomal recessive mode of inheritance of the disease. Then there were reports of the possibility of autosomal dominant transmission of the disease. The observed family cases of pathology could serve as confirmation of these hypotheses. However, most of the described clinical observations of Prader-Willi syndrome were sporadic.

Subsequent studies made it possible to establish certain chromosomal abnormalities in children with Prader-Willi syndrome. Cytogenetic analysis showed that chromosomal abnormalities in patients were either translocations (t 15/15) or mosaicism. In 1987, the first reports of a microdeletion of chromosome 15 appeared. However, the final identification of chromosomal changes in Prader-Willi syndrome became possible only after the introduction of molecular genetic research methods into practice.

It has now been established that the development of Prader-Willi syndrome is associated with damage to the critical region of chromosome 15 (segment q11.2-q13). At the same time, it turned out that damage to the same region of chromosome 15 is also observed in another disease - Angelman syndrome, the clinical picture of which differs significantly from Prader-Willi syndrome and is characterized by an early (at the age of 6-12 months) slowdown in psychomotor development, microcephaly, speech impairment ( in 100% of cases), ataxia, uncontrolled violent laughter, frequent epileptiform seizures, a specific facial expression.

Thus, despite the damage in the Prader-Willi and Angelman syndromes of the same locus of chromosome 15, the clinical manifestations of both diseases are sharply opposite.

An explanation of phenotypic differences has been obtained only in recent years. It turned out that the development of these diseases is associated with new genetic phenomena - genomic imprinting and uniparental disomy.

Genomic imprinting is a new phenomenon discovered thanks to the advances in molecular genetics. It means different expression of genetic material (homologous alleles) in chromosomes depending on paternal or maternal origin, i.e. indicates the influence of parents on the phenotype of the child. Until now, it was believed that the contribution to the manifestation (expression) of the genes of the father and mother is equivalent.

In fact, genomic imprinting is a sexual and tissue-dependent complex modifier of the gene activity of some loci of chromosomes, depending on their parental origin. Manifestations of genomic imprinting have also been identified in other diseases - Sotos, Beckwith-Wiedemann, Silver-Russell syndromes, cystic fibrosis, and others.

Uniparental (uniparental) disomy - inheritance of both chromosomes from only one of the parents. For many years it was believed that such inheritance was impossible. Only with the help of molecular genetic markers was it possible to prove the possibility of uniparental disomy. The nature of uniparental disomy has not been completely elucidated, but it has been established that it owes its origin to a number of genetic and biochemical disorders.

It should be noted that it is impossible to detect a microdeletion or uniparental disomy using a conventional study of the chromosomal composition of the karyotype. For this, special cytogenetic and molecular genetic methods are used - prometaphase analysis, the use of DNA markers of certain sections of chromosome 15 (study of methylation processes), etc.

To date, Prader-Willi and Angelman syndromes serve as a generally accepted model for studying new and complex phenomena in clinical genetics - genomic imprinting and uniparental disomy.

It has been established that Prader-Willi syndrome can be caused by two main mechanisms. The first of these is a microdeletion of chromosome 15 (15q11.2-q13), which is always of paternal origin. The second is maternal isodysomy, i.e. when both chromosomes 15 are from the mother. The development of Angelman syndrome, on the contrary, is associated with a microdeletion of the same region of chromosome 15, but of maternal origin, or paternal isodisomy. Most (about 70%) cases of Prader-Willi syndrome are due to microdeletion, the rest are due to disomy. At the same time, the absence of clinical differences between patients with microdeletion and isodisomia attracts attention.

Pathogenesis:

The pathogenesis of the Prader-Willi syndrome remains poorly understood to date. It is suggested that in patients it is due to a significant (more than 10 times) increase in fat synthesis from acetate and extremely low lipolysis processes.
according to the hypogonadotropic type, it can be associated with dysfunction of the hypothalamus, mainly in the region of the ventromedial and ventrolateral nuclei. The correctness of this point of view is confirmed by the effectiveness of the treatment of patients with pharmaceutical preparations (clomiphene), which led to an increase in plasma levels of luteinizing hormone, testosterone, normalization of renal excretion of gonadotropins, spermatogenesis, and the appearance of secondary sexual characteristics.

One explanation for hypopigmentation of the skin, hair, and iris is a decrease in tyrosinase activity in hair follicles and melanocytes, as well as a decrease in pigment in the retina.

Attention is drawn to the increased risk of leukemia in patients with Prader-Willi syndrome. Studies have revealed a decrease in DNA repair (up to 65% compared to 97% in a healthy child) in lymphocytes of patients with this pathology. It is possible that low DNA repair capacity can play a fatal role in the development of malignant neoplasms in individuals with Prader-Willi syndrome.

Symptoms of Prader-Willi Syndrome:

Children with Prader-Willi syndrome are usually born full-term with slight intrauterine malnutrition and often in. In 10-40% of cases, breech presentation is observed.

During the course of the disease, two phases can be distinguished: the first is characteristic of children 12-18 months of age. It is characterized by severe muscle hypotension, decreased reflexes - Moro, sucking and swallowing, which makes it difficult for the child to feed. The second - comes later, in a few weeks or months. A constant feeling of hunger appears, leading to the development of obesity, and the deposition of fat is observed mainly on the trunk and in the proximal limbs.

Muscular hypotension gradually decreases and almost completely disappears by school age. The feet and hands of patients are disproportionately small - acromicria. In children, hypogonadism is noted (in boys - hypoplasia of the penis, scrotum, and in girls - underdevelopment of the labia and in 50% of cases - the uterus).

The growth of patients is often reduced. In 75% of children, hypopigmentation of the skin, hair and iris is observed. Often diagnosed. Psychomotor development lags behind the age norm - the coefficient of intellectual development is from 20 to 80 units. (at a rate of 85-115 units). Speech is difficult, vocabulary is reduced. Patients are friendly, the mood is characterized by frequent changes. Disorders of coordination, strabismus are described.

There are other anomalies: microdontia, hypoplasia of the cartilage of the auricles, ectropion (eversion of the eyelid),.

Prader-Willi syndrome was first described in 1956. The cause of this syndrome is the loss of function of chromosomal regions located in the proximal part of the long arm of chromosome 15 (15q11-13). The deletion is of paternal origin and is observed in 70% of patients, in 5% the disease is associated with a rearrangement of chromosome 15. In most cases, the disease occurs de novo, in 25% of cases the syndrome occurs as a result of uniparental disomy. In some patients, the chromosomal abnormality cannot be identified, but they have a characteristic clinical picture of Prader-Willi syndrome.

The main clinical signs are mental retardation, inadequate behavior, delayed physical development, short stature, and hypotension. Some clinical signs in this disease can be observed up to 3 years of age (muscular hypotension, low weight and feeding difficulties), others begin to predominate after 6 months of age (obesity, increased appetite, mental retardation, growth retardation). Along with dysplastic signs (drooping corners of the mouth, high palate, hypertelorism, epicanthus, small feet and hands, almond-shaped eyes, dermatoglyphics anomalies), hypogonadism is detected due to low levels of sex hormones, hypopigmentation (75% of patients). It should be noted that Prader-Willi syndrome is characterized by a wide clinical polymorphism, therefore, it is necessary to carry out differential diagnosis with Cohen, Opitz-Frias, Bardet-Biedl syndromes.

Life expectancy is 25 - 30 years.

Diagnosis of the disease is carried out using DNA analysis or the FISH method. The risk for proband siblings is about 1%.

Angelman syndrome

If the main reason for the occurrence of Prader-Willi syndrome was the deletion of the proximal part of the long arm of chromosome 15 of paternal origin, then a similar loss of the same part of the long arm of chromosome 15, but only of maternal origin, causes the development of another pathology - Angelman syndrome. With this disease, a completely different clinical picture develops. Angelman's syndrome is characterized by: severe oligophrenia, speech delay, hyperactive behavior, convulsions, large lower jaw, macrostomia, hypopigmentation (in 40% of patients). They start walking late, they are characterized by a gait with widely spaced legs, elbow joints are bent; violent unmotivated laughter is noted, there are pronounced disorders of coordination of movements.

Differential diagnosis should be carried out with Peters-Plas syndrome, Rett syndrome and with Opitz trigonocephaly.

The frequency of the syndrome in the population is 1:20,000.

Approximately 20 - 30% of patients do not have a deletion of the proximal part of the long arm of chromosome 15; in a small number of patients, the cause is uniparental disomy. Diagnosis of the syndrome is carried out by the same methods as in Prader-Willi syndrome, i.e. DNA analysis and FISH method are carried out. Using these methods, it is possible to establish the etiology of about 90% of cases of the disease. The risk to the siblings of the proband is not known.

Prader-Willi syndrome is a rare genetic anomaly. In Prader-Willi syndrome, approximately 7 genes from chromosome 15 are missing.

Peculiarities

Prader-Willi syndrome is characterized by:

• before birth: low fetal mobility;
• often - the wrong position of the fetus;

• obesity; tendency to overeat;
• decreased muscle tone (hypotonicity); reduced coordination of movements;
• small hands and feet, short stature;
• increased drowsiness;
• strabismus (strabismus);
• scoliosis (curvature of the spine);
• decreased bone density;
• reduced function of the sex glands (hypogonadism); as a result, as a rule, infertility;

• speech delay, mental retardation; lag in mastering the skills of general and fine motor skills.
• later puberty.

External signs: in adults, the bridge of the nose is pronounced; the forehead is high and narrow; the eyes are usually almond-shaped; lips are narrow.

Diagnostics

The syndrome is diagnosed by genetic testing recommended for newborns with low muscle tone (hypotonicity). Sometimes, instead of diagnosing Prader-Willi syndrome, doctors mistakenly diagnose Down syndrome (since Down syndrome is much more common).

Treatment

Prader-Willi syndrome is a congenital genetic anomaly and therefore cannot be cured.

However, some treatment measures improve the quality of life of people with the syndrome.

In particular, infants with hypotension should receive massage and other special therapies.

Hypogonadism usually presents with micropenia and undescended testicles in boys (cryptorchidism); doctors may recommend waiting for the testicles to descend on their own or recommend surgery or hormone therapy.

To correct increased weight, a diet with a restriction on the amount of fats and carbohydrates is used. Due to the obesity that accompanies the syndrome, the amount and quality of food consumed by a person with Prader-Willi syndrome must be closely monitored (usually people with this syndrome are able to eat a lot without eating up).

Sleep apnea (holding your breath during sleep) can be a possible complication.

Risks

The risk that the next child of the same parents will also be born with Prader-Willi syndrome depends on the mechanism that caused the genetic failure.

This risk is less than 1% if the first child has a gene deletion or parthenogenetic (uniparental) disomy; up to 50% - if the failure is caused by a mutation; up to 25% - in case of translocation of parental chromosomes. Parents are encouraged to undergo genetic testing.

Development prospects

Most people with Prader-Willi syndrome have delayed mental and speech development. According to Kerfs and Freem (1992),

• 5% of those surveyed demonstrated an average level of IQ (more than 85 points on a scale);
• 27% - the level is on the verge of the average (70-85 points);
• 34% - the level of weak backlog (50-70 points);
• 27% - the level of average backlog (35-70 points);
• 5% - a strong lag (20-35 points);
• less than 1% - a significant lag.

According to other studies (Cassidy), 40% of patients with Prader-Willi syndrome demonstrate intelligence on the verge of average or reduced intelligence.

As a rule, children with Prader-Willi syndrome have good long-term visual memory, they can learn to read, they can have a rich passive vocabulary, but their own speech is usually worse than understanding. Auditory memory, math and writing skills, visual and auditory short-term memory are usually significantly worse in these children.

Prader-Willi syndrome is often associated with increased appetite, this is due to the fact that the 15th chromosome is associated with the hypothalamus. (However, autopsies of those with Prader-Willi syndrome did not reveal any defects in the hypothalamus.)

Links

• L. Z. Kazantseva, P. V. Novikov, A. N. Semyachkina, E. A. Nikolaeva, M. B. Kurbatov, E. V. Dobrynina. Prader-Willi syndrome in children: new in etiology, pathogenesis and treatment. Moscow Research Institute of Pediatrics and Pediatric Surgery of the Ministry of Health of the Russian Federation
• Uniparental disomy on the website "Human Biology"

Wikimedia Foundation. 2010 .

• - (Prader Mlli syndrome) a congenital disease characterized by obesity, combined with mental retardation and the presence of too small genital organs in a person; patients with this syndrome often develop diabetes mellitus ... Explanatory Dictionary of Medicine

A congenital disease characterized by obesity, combined with mental retardation and the presence of too small genital organs in a person; Patients with this syndrome often develop diabetes mellitus.