Angelmann syndrome in children and adults
There are a number of diseases in which expressions like "take care of yourself and not get sick" sound, at least, ridiculous. This pathology, in which some mental and physical abnormalities are embedded in the body of a child even before birth, but the parents do not have any guilt. Such diseases are caused by mutations or disorders in chromosome sets and are called chromosomal or genetic. Angelman syndrome, Down syndrome, Patau, Edwards, Turner, Prader-Willi are just a part of the genetic diseases from a fairly decent list.
Syndrome of a happy person
This time we will talk about a pathology named after the pediatrician from England, Harry Angellman, who first raised the issue of this problem in 1 965, having faced the day before in his practice with three unusual children, united by common peculiar symptoms. The doctor named these children puppet children and wrote about them an article that was originally called "Puppet Children". The article itself and its name were written under the impression of a picture seen in one of the museums in Verona. The picture depicted a laughing boy, and it was called "Boy-puppet." The association of the child depicted in the picture with the three children that Angelman once encountered in his practice, and encouraged the pediatrician to unite the children in one group due to their existing disease.
The fact that the children noted in the article were not noticed by other doctors is not surprising. After all, at first glance it seemed that they had completely different diseases, so the general clinical picture of the disease differed in 3 different cases. A "new" chromosomal pathology might be of interest to other scientists, but at that time genetics was not yet developed enough to confirm the hypothesis of an English doctor. Therefore, the article after a certain interest in it for a long time was abandoned to the distant regiment.
The next mention of the Angelman syndrome, and so it was now called the article of the pediatrician from England, G. Anglemann, dates back to the beginning of the 80s of the 20th century. And only in 1987 it was possible to find the reason why a small part of children are born with such deviations, that from the side they seem constantly smiling and happy. In fact, this is not so, and the smile is just a grimace, behind which lies the unhappy human soul and the pain of the parents.
Chromosomal mutation in a child, according to statistics, can develop both against the background of such mutations in the parents, and in the absence of such. There is no clear hereditary character in Angelman syndrome (SA), but the probability of developing pathology in parents with chromosomal mutations is quite high.
It is also interesting that if a family already has a child with a SA, there is a one percent chance of having a second child of the same type, even if the parents are healthy.
There are still no exact statistics on the number of patients with Anghelman's syndrome. Perhaps the fault is a variety of symptoms that can occur in a certain composition or for a long time do not arise at all. It is assumed that the prevalence of the disease is: 1 child per 20,000 newborns. But this figure is very approximate.
Causes of the angelman syndrome
Angelmann syndrome is the medical name for chromosomal pathology, but it is by no means the only one. In people this disease is also called the syndrome of puppet children, and the syndrome of a happy puppet, and the syndrome of Petrushka, and the syndrome of a laughing doll. Yes what kind of names people can not come up with (sometimes even insulting for the patients themselves and their parents), but the disease is a disease, no matter how funny it looks outwardly and whatever the reasons may be caused.
And the reasons for the development of Angelman syndrome, as well as many other genetic pathologies, in all cases are violations in the structure of one of the chromosomes or the chromosome set as a whole. But only in our case, the whole problem lies in the 15 chromosomes transmitted from the mother. Those. The paternal chromosome in this case does not have any deviations, but the female undergoes certain mutations.
According to the type of chromosomal abnormality, Angelmann's syndrome refers to chromosomal mutations. Such mutations are:
- Deletion (the absence of a region of a chromosome containing a specific set of genes, if one of the genes does not refer to microdeletion) is the result of two discontinuities and one reunion, when the region of the original chromosome is lost.
- Duplication (the presence of an extra site in the chromosome, which is a copy of the already available), which in most cases leads to the death of a person, less often - to infertility.
- Inversion (reversal of one of the chromosome segments by 180 degrees, that is, in the opposite direction, and then the genes in it turn out to be arranged in the reverse order), when the broken ends of the chromosome are connected in an order different from the original one.
- Insertion (if part of the genetic material in the chromosome is not in its place),
- translocation (if a part of the chromosome joins another chromosome, such a mutation can be mutual without loss of sites).
Getting a mutated chromosome from an unsuspecting mother, the baby is doomed to be born with deviations in advance. The most common cause of Anghelman's syndrome development is still the deletion of the maternal 15 chromosome, when there is no small area in it. Less commonly occurring mutations in the syndrome of the "laughing doll" are:
- single-father diosomia (if the child received a pair of chromosomes from the father, the mother chromosome is absent)
- mutation of genes in the DNA, which are both the main building material (genetic) material and the instruction for its correct use (in particular, mutation of the ube3a gene in the maternal chromosome).
The presence of one of such mutations in the parents is a risk factor for Anghelman syndrome in children. But not only chromosomal mutations, but also genomic mutations (which are associated with a quantitative change in chromosome sets and are found more often than chromosomes) can provoke the development of the disease in the child. To common genomic mutations can be attributed trisomy of chromosomes (if a person has a chromosome set has more than 46 chromosomes).
To the pathology of the baby does not necessarily have to have parents have chromosomal abnormalities. And yet there is a certain percentage of patients whose disease is hereditary.
Let's dig a little in biology, more precisely in genetics. The genetic information of each individual human body is contained in 23 pairs of chromosomes. One chromosome from the pair is transmitted to the child from the father, the other from the mother. All pairs of chromosomes differ in shape and size and carry in themselves certain information. So, 23 pairs of chromosomes (X and Y chromosomes) is responsible for the formation of the child's sexual characteristics (XX - girl, XY-boy, while the Y-chromosome the child can only get from the father).
Ideally, a child receives from his parents 46 chromosomes, which form his genetic attributes, predetermining him as an individual. A greater number of chromosomes is called trisomy and is considered a deviation from the norm. For example, the presence of 47 chromosomes in the chromosome set (karyotype, which determines species and individual characteristics) causes the onset of Down syndrome.
If the chromosomes are tinted with a special dye, then in the microscope one can see bands of different shades along each of them. Within each band is a huge number of genes. All these bands are numbered by scientists and have a fixed location. The absence of one of the bands is considered a deviation from the norm. With Angelmann syndrome, you can very often observe the absence of segments of the maternal chromosome in the interval q11-q13 located in the long arm, the number of DNA bases in which is only about 4 million.
The main component of the chromosome is an incredibly long DNA molecule containing thousands of genes and tens and hundreds of millions of nitrogenous bases. Thus, the 15 chromosomes responsible for the development of Angelman's syndrome and several others, contains 1200 genes and about 100 million bases. Any violations in the structure of the DNA molecule will necessarily affect the appearance and development of the unborn child.
The genetic information contained in the genes is converted into a protein or RNA. This process is called gene expression. Thus, the genetic information received from parents receives both form and content, embodied in their unique heir to the female or male sex.
There are a number of pathologies with a nonclassical type of inheritance, including the Angelmann syndrome, in which the genes obtained from parents in the pair chromosomes bear a peculiar imprint of the parents and manifest themselves in different ways.
So, Angelmann syndrome is a vivid example of genomic imprinting, in which the expression of genes in the child's body is directly dependent on which parent was given alleles (different forms of the same gene from the father and mother located on identical sections of the pair chromosomes) . Those. To the emergence of the syndrome lead only anomalies in the maternal chromosome, while mutations and disruptions in the structure of the paternal chromosome cause completely different pathologies.
In this pathology, there is a lack of certain genes in the maternal chromosome or a loss / decrease in the activity of individual genes (in the overwhelming majority of cases of the ube3a gene involved in the metabolism of ubiquitin, a protein regulating the degradation of other proteins). As a result, the child is diagnosed with mental development abnormalities and physical deformities.
Symptoms of the angelman syndrome
The symptomatology of Angelman's syndrome affects various aspects of a child's life and development: physical, neurological, psychic. Based on this, we can distinguish 3 groups of symptoms that indicate the development of this pathology.
- External or physical symptoms:
- a disproportionately small head compared with the trunk and limbs that are of normal size,
- too wide mouth,
- on the face there is almost always a smile (with an open mouth),
- rare teeth,
- narrow upper lip,
- often sticking out a wide tongue,
- protruding lower jaw,
- a pointy chin,
- very light skin, often also hair (albinism, associated with the fact that the body does not produce the pigment melanin),
- dark spots on light skin (hypopigmentation due to insufficient production of melanin)
- physical or external symptoms: eye diseases such as strabismus or atrophy of the optic nerve,
- curvature of the spine (scoliosis),
- stiff legs (when walking a man does not bend his knees due to the small mobility of the joints, hence the comparison with the puppet gait).
- Symptoms associated with mental and emotional development:
- a strong lag in mental development,
- unnecessarily emotional, noisy, fussy behavior,
- frequent clapping,
- the expressed friendliness, underlined by a constant smile on the face,
- frequent, causeless laughter.
- Neurological symptoms:
- tremor of extremities,
- insufficient coordination of movements with loss of balance,
- decreased muscle tone,
- a variety of sleep disorders,
- frequent hysterical seizures in childhood,
- speech impairment (the child begins to speak late, has poor communication skills and slurred speech),
- hyperactivity against a background of increased excitability,
- difficulties with concentration and training.
But this is a generalized picture of the disease. In fact, the clinical picture of Anghelman's syndrome largely depends on the stage of development of the disease and the type of chromosomal mutation that caused the pathology. And this means that in different patients the symptomatology of the disease may differ significantly, which for a long time did not allow isolating pathology among others with a similar clinical picture.
Among the total number of symptoms can be identified such that are characteristic of all patients without exception:
- severe deviations in mental development,
- inadequate behavior (causeless laughter, increased excitability, poor concentration of attention, a state of euphoria),
- underdevelopment of motor skills,
- poor coordination of movements, ataxia of walking (uneven pace, swinging from side to side, etc.), tremor of extremities.
- violation of speech development with the predominance of non-verbal means of communication.
Among the symptoms that occur in the vast majority of patients, we can distinguish such:
- disproportionate head and trunk, caused by a delay in physical development,
- in many patients the shape of the skull is such that the size of the brain remains smaller than in healthy people (microcephaly),
- epileptic seizures in the age of up to 3 years with a progressive decrease in strength and frequency in the elderly,
- distortion of EEG indices (oscillations and high amplitude of low frequency waves).
These symptoms occur quite often, nevertheless in 20% of patients with Angelmann's syndrome they are absent.
Even more rarely can diagnose such manifestations of the disease as:
- pronounced or slight strabismus,
- a weak control over the movement of the tongue, as a result of which patients often stick out their tongue for no reason,
- difficulties with swallowing and sucking, especially in younger children,
- violation of skin and eye pigmentation,
- raised or bent during walking hands,
- sleep disorders, especially in childhood,
- frequent salivation,
- irrepressible thirst,
- excessively active chewing movements,
- hypersensitivity to heat,
- flat head,
- advanced lower jaw,
- smooth palms.
Quite a large percentage of patients have problems with urination, which they poorly control, violation of fine motor skills, which creates difficulties in self-service and training, overweight. Practically in all patients puberty begins later than in healthy peers.
Children with angelman syndrome are good at understanding and understanding oral speech, but do not want to participate in the conversation, limiting their speech to dozens of words necessary in everyday life. But in adulthood such patients look younger than their peers without genetic pathologies.
Many of the symptoms of Angelmann's syndrome are fickle, so the clinical picture of the disease changes with age. Seizures and epileptic seizures become more rare or disappear at all, the patient becomes less agitated, sleep sets in.
Complications and consequences
Angelman syndrome is a serious, practically incurable to date chromosomal pathology, which deprives patients of the opportunity to live a normal life. What will be the life of the baby with the SA, depends to a large extent on the type of chromosomal abnormality.
Duplication of the chromosome region in most cases is incompatible with life. And even if such patients do not die in infancy and reach puberty, they have no possibility of having children.
The deletion or absence of a part of the genes that occurs in Anghelman's syndrome most often is an obstacle to the child learning to walk and talk. In such children, mental retardation is presented in a more severe form, epilepsy attacks often occur, and their intensity is much stronger than in patients with other chromosomal abnormalities.
If there is only a mutation of one gene, with due attention and approach the child can be taught the basics of self-service, communication and communication in the team, although he will still lag behind in development from his peers.
For children with Angelmann's syndrome, benevolent by nature, the main is the love and attention of parents. Only in this case the training of the child will bear fruit, even small ones. Of course, patients in the regular school will not be able to study with the SA. They need special classes, where children will first be taught to concentrate their attention, and then they will gradually give the basics of school knowledge.
Diagnostics of the angelman syndrome
Angelman syndrome is a congenital pathology of development. But due to some circumstances, diagnosing it in infancy and early childhood is most often not possible. The reason for this is nonspecificity and mild symptoms in infants and toddlers up to 3 years. And the prevalence of the disease in our country is not so great that doctors have learned to recognize it among its like.
Angelmann syndrome in infants can manifest as a reduced muscle tone, which manifests itself as eating problems (weakness of the sucking and swallowing reflex), and later difficulties in learning to walk (such children begin to walk much later). These symptoms are the first signs of a deviation in the development of the baby, which may well be associated with a chromosomal abnormality. Confirm this assumption can only genetic analysis.
Particular attention is paid to children whose parents have different genomic or chromosomal abnormalities. After all, the disease can not manifest itself in any way, and if the pathology is revealed on time, by starting to work hard with the child, it is possible to achieve much greater success in training, slowing the progression of the disease.
If the parents have different chromosomal abnormalities, the genetic analysis is carried out even before the baby is born, since the CA is one of the pathologies that can be detected in an embryonic state.
The collection of material for genetic research can be done in two ways:
- invasive (with a certain percentage of risk, because it is required to enter the uterus in order to take a test of amniotic fluid),
- non-invasive (DNA analysis of the baby by the mother's blood).
Then the following researches are carried out:
- fluorescent in situ hybridization (FISH method) -binding of a DNA probe labeled with a special dye to the DNA under study, followed by a microscopic examination.
- analysis of mutations in the ube3a gene and imprinting genes,
- analysis of DNA methylation with the help of special methods used in genetics.
Genetic analyzes give quite accurate information in the case of chromosomal abnormalities, so future parents know in advance what they should be prepared for. Nevertheless, there are exceptions. In a certain group of patients, in the presence of all symptom-indicating symptoms, the results of the analyzes remain normal. Those. To reveal a pathology it is possible only closely observing the child from the earliest childhood: how eats, when he began to walk and speak, whether legs bends when walking, etc.
In addition to the FISH method, tomography (CT or MRI) can be identified among the methods of instrumental diagnosis in Anghelman's syndrome, helping to determine the condition and size of the brain, and an electroencephalogram (EEG) showing how individual brain regions work.
The final diagnosis of the doctors is usually set at the age of 3-7 years, when the patient already has the majority of symptoms and the dynamics of the disease development is visible.
The Angelman syndrome is a genetic pathology that does not actually have specific manifestations. Most of the symptoms can equally indicate both CA and other genetic pathologies.
Differential diagnosis in Anghelman's syndrome is carried out with the following pathologies:
- Pitt-Hopkins Syndrome (patients are characterized by mental retardation, cheerful character, smiling, they have a rather large and wide mouth, microcephaly is noted). Difference - attacks of hyperventilation and delay of breathing in waking state.
- Syndrome Kristiansona (patients mentally retarded people with a cheerful disposition, unable to talk, they are characterized by microcephaly, ataxia, convulsions, involuntary movements of the muscles).
- Mowata-Wilson syndrome (symptoms: mental retardation, epileptic seizures, sharp chin, open mouth, expression of happiness on the face, microcephaly). The difference is a large distance between the eyes, the eyes are chamfered inward, the tip of the nose is rounded, the auricle is turned back.
- Kabuki syndrome (characterized by mild and moderate degree of mental retardation, speech and motor problems, muscle weakness, epileptic seizures, microcephaly, large intervals between pruritus, impaired coordination). Difference - eyebrows in the form of an arch, inverted lateral part of the lower eyelid, wide-set eyes, long eye slits with long thick lashes.
- Rett syndrome (differentiation with CA in women). Symptoms: delayed speech development, convulsive seizures, microcephaly. The difference - there is no happy expression on the face, there are attacks of apnea and apraxia, which eventually progresses.
- Syndrome of autosomal recessive mental tardiga 38 (symptoms: marked mental retardation with a delay in the development of motor skills and speech, muscle weakness, problems with feeding in infancy, impulsivity). The difference is the blue color of the iris.
- Syndrome of duplication of the gene MESR 2 (differentiation with SA in men). Symptoms: severe mental retardation, muscle weakness from childhood, problems with speech or lack of it, epilepsy. Differences - progressive myopathy, constantly recurring infections.
- Clifstra Syndrome (symptomatic: speech and thinking problems, muscle weakness, sleep disorders, lack of attention, a slightly open mouth, hyperactivity, convulsions, ataxia, imbalance). Differences - a flat face, short snub nose, wide-set eyes, large inverted lower lip, attacks of aggression.
- Syndrome Smith-Magenis (characterized by seizures, problems with sleep, intellectual and motor development disorders). Differences - a broad and flat face, convex forehead.
- Kulena-de Vries syndrome (mild and moderate mental retardation, muscle weakness, convulsive attacks, friendliness). Differences - a long face with a high forehead, protruding ears, oblique eyes, greater mobility of joints, congenital heart pathologies.
- Syndrome Philan - McDermid (symptoms: mental retardation, speech impairment or lack thereof). Differences - large hands with developed muscles, muscle weakness since birth, weak sweating.
Angelman syndrome similar symptoms can "boast" and how such a pathology adenilsuktsinazy deficiency, an autosomal recessive syndrome of mental retardation 1, the chromosome 2q23.1 duplication syndrome, haploinsufficiency genes FOXG1, STXBP1 or MEF2C and others.
The doctor's task is to make an accurate diagnosis, differentiating Angelmann's syndrome from pathologies with similar symptoms, and to prescribe an effective treatment that is relevant for the diagnosed degree of the disease development.
Treatment of the angelman syndrome
Angelman syndrome refers to the category of those pathologies, the search for effective treatment of which medicine is engaged to this day. The etiological treatment of the disease is in the development stage of various methods and means, many of which have not yet been tested in humans. So for the time being, doctors have to limit themselves to symptomatic therapy, which helps at least somehow alleviate the unenviable situation of children and adults with a puppet syndrome suffering from epileptic seizures, salivation, hypotension and sleep disorders.
So reduce the frequency and strength of epileptic seizures can be with a properly selected anticonvulsant drug. But the whole difficulty is that seizures in patients with AS differ from the usual epileptic seizures in that they are characterized by several types of convulsions, which means that it will be possible to ease the condition by the administration of several drugs at once.
The most popular anticonvulsants used to treat Anghelman syndrome are: valproic acid, topiramate, lamotrigine, levetiracetam, clonazepam and preparations based on them. Less commonly used drugs based on karmazepina, phenytoin, phenobarbital, ethosuximide, as some of them can provoke a paradoxical effect, which is to increase and increase the frequency of epileptic seizures. This happens if the drug is used as part of monotherapy.
For the treatment of salivation, two methods are usually used: medicinal (preparations suppressing the formation of saliva) and operational, consisting in reimplantation of the salivary ducts. But in the case of CA, these methods are considered ineffective, and the question remains open. Parents and those who care for such patients, we have to pay special attention to this moment, since the patients themselves usually do not control salivation, and some simply can not take care of themselves.
Another problem is the short duration of sleep. Often children with Angelman's syndrome sleep no more than 5 hours, which negatively affects the work of the whole organism. Excitable, active children, loving games and communication (even if they try to confine themselves to non-verbal ways), are noticeably tired for the day. To have a good rest, the body needs a sound full sleep, but that's just the trouble with it.
It would seem that to improve sleep in excitable patients should be sufficient drugs with sedative effect (phenothiazines and atypical antipsychotics), calming the nervous system. But in the case of CA, the use of such drugs is fraught with the appearance of negative effects. Therefore, doctors prefer nevertheless to light hypnotic drugs, such as "Melatonin" (a natural hormone drug based on the sleep hormone), which give patients an hour before going to bed in the amount of 1 tablet, and "Diphenhydramine." the frequency of administration and dosage of which is set by the doctor, depending on the condition and age of the patient.
Sometimes patients with angelman syndrome have problems with digestion and stool. To adjust a chair it is possible by means of laxative preparations (it is better than a phytogenesis).
And you can approach the problem differently, as the American doctors did, based on some methods of treating autism, because many of the symptoms characteristic of CA are also characteristic of autism (impulsivity, involuntary movements, repetitive actions, violation of attention, communication problems, etc. .). It was noted that the administration of the hormone secretin, normalizing digestion and stools, positively affects the attention of patients, and oxytocin helps improve the child's cognitive abilities and memory, and correct behavior.
True, some hormones are indispensable here, especially when it comes to children. Angelman syndrome shows behavioral therapy, work with a psychologist and speech therapist (teaching non-verbal ways of communication and sign language). The training of such children should be based on an individual program with the participation of specially trained teachers, a psychologist and parents. Unfortunately, this is not possible everywhere, and families remain alone with their problem.
Since many small patients with CA suffer from low muscle tone and joint problems, much attention is paid to physiotherapeutic treatment. Most often, doctors resort to the use of paraffin applications, electropherosis, magnetotherapy.
Active toning massage and special exercises of physiotherapy will help the sick child after a while to stand confidently on his feet and walk. Especially useful in this regard aquagymnastics, which is recommended in CA in cool water. It increases the tone of the muscles and teaches the baby to own his body, coordinate movements.
The most dangerous symptom in Anghelman's syndrome is seizures, similar to epileptic seizures. This symptom is observed in 80% of patients, which means that all of them should be prescribed effective anticonvulsant treatment.
Treatment of epileptic seizures is carried out with the help of vitamins and anticonvulsants. In Angelman syndrome, accompanied by convulsive syndrome, B vitamins, as well as vitamins C, D and E will be helpful . But prescribing vitamin therapy alone is very dangerous in this case, because uncontrolled intake of vitamins can reduce the effectiveness of antiepileptic drugs and provoke new, more severe and prolonged seizures.
The choice of anticonvulsant drugs and the appointment of their effective dosage should also be handled by a specialist doctor. He also decides whether there will be enough of one drug or the patient will have to take 2 or more medicines for a long time .
For most patients, doctors prescribe valproic acid preparations (Valproic Acid, Depakin, Convuleks, Valparin, etc.), which prevent seizures, improve the mood and mental state of patients.
Valproic acid is available in the form of tablets, syrup and injectable solutions. The most popular drug is the drug of prolonged action "Depakin" in tablets and as a solution for intravenous administration. The dosage of the drug is determined by the doctor individually depending on the weight, age and condition of the patient.
Take the drug during meals 2 to 3 times a day. The average daily dose is 20-30 mg per 1 kilogram of the patient's weight, the maximum is 50 mg / kg per day.
Contraindications. It is not used for violations of the liver and pancreas, hemorrhagic diathesis, hepatitis, porphyria and hypersensitivity to the drug.
Among the side effects can be distinguished hand trembling, digestion and stool, changes in body weight.
"Topiramate" is also a drug of choice in CA. It is made in the form of tablets and is used as a part of monotherapy, and in combination with other medicines.
Method of application and dosage. Take pills inside without regard to food intake. The initial daily intake for adults is 25-50 mg, for children 0.5-1 mg / kg. Each week, the dosage is increased according to the prescription of the doctor.
The drug should not be taken during pregnancy and lactation, as well as with increased sensitivity to its components. The medicine has many different side effects.
Drugs that can be prescribed by a doctor in Angelmann's syndrome: Clomazepam, Rivotril, Lamotrigine, Seizar, Lamictal, Levetiracetam, Keppra, Epitera, and others.
Alternative treatment and homeopathy
Alternative medicine, like homeopathic drugs, certainly differ comparative safety, but here the effectiveness of such treatment in relation to Angelholm's syndrome can be considered controversial.
Although some alternative treatments can still help. It's about stopping epileptic seizures. In this regard, herbal therapy can be quite effective.
A good effect is provided by a medicinal fee based on peony, licorice and duckweed (components are taken in equal amounts). Grasses need to be ground into flour. After 2 weeks from the beginning of the reception, you can notice a significant decrease in the frequency of convulsive attacks.
Useful for cramps and a decoction of lavender (1 tsp for a glass of boiling water). The formulation is boiled for 5 minutes and insisted for half an hour. Take the medicine overnight for 14 days.
Effective for epileptic attacks is considered water (or alcohol) infusion motherwort.
From preparations of homeopathy for the prevention of convulsive attacks in the Angelman syndrome, you can use medicines based on chamomile and motherwort, Acidum hydrocyanicum, Argentum nitricum, Kalium bromatum, Arsenicum album. But it is necessary to consider that effective and safe doses of preparations in each concrete case can appoint only the doctor a homeopathist.
As the reader has probably already understood, to prevent the mutation of genes and other chromosomal abnormalities, medicine is still beyond the power, however, as well as to remedy the situation. This can happen to everyone, because children with Angelmann syndrome are born also in healthy parents, and genetics, which at the moment is one of the least studied branches of medicine, can not yet explain this.
The only thing that can be done is to take responsibility responsive to pregnancy planning, to be registered and examined on time. But again, such a measure would rather not be prophylactic, but cognitive, like any survey. But young parents in advance will know what to prepare for, and in case of a positive answer they will decide whether they will be able to take on such responsibility as raising a sick child.
The prognosis for Anghelman's syndrome depends on the nature of the chromosomal abnormality and the timeliness of its detection. The hardest part is for those children whose 15 chromosomes contain "missing" genes (deletion). The likelihood of walking and talking in such patients is extremely small. The remaining cases with an attentive approach and love for your child are amenable to correction.
Such patients, alas, can not become full members of the society, despite the fact that they are far from stupid, they understand the speech and its meaning. Here are just problems with communication they have for life. Patients can be taught sign language from childhood, but one can not be forced to communicate with words. The lexicon of "talking" patients is limited to a minimum of words used in everyday life (5-15 words).
As for the life expectancy and general health of patients with Anghelman's syndrome, the figures here fluctuate on average. In adulthood, patients generally face health problems such as scoliosis and obesity, which, with the right approach to treatment, are not life threatening.