Causes
If there is no family history of this disease, and the parents are in absolute health, there is still a risk of having a child with this disease. Science knows that a human cell contains 46 chromosomes. The egg and sperm contain twenty-three chromosomes. When they combine, the number of chromosomes also combines. The causes of Edwards syndrome are not well understood to date.
Researchers say that due to gene mutations, an extra one is formed in the 18th pair of chromosomes. In 2 cases of this disease out of 100, the eighteenth chromosome is lengthened, while the 47th chromosome is not formed, but a translocation occurs.
In three out of a hundred cases of the disease, doctors talk about mosaic trisomy. This means that the extra chromosome is present only in some cells of the fetal body, and not in absolutely all. But in terms of symptoms, the three described variants of the disease converge. Only in the first case can the course be severe and there is a greater chance of death.
Risk factors
There are some factors that can influence improper cell division:
1. Mother's age. It has long been proven that the risk of developing chromosomal pathologies increases in direct proportion to the age of the mother. Although this connection is less pronounced in Edwards syndrome than in other similar diseases (for example, Down syndrome). However, for women over 40 years of age, the likelihood of having a child with this anomaly is approximately 6–7 times higher.
2. Alcohol and smoking. Abuse of these bad habits can adversely affect the reproductive system, further affecting the division of germ cells.
3. Taking medications. Some medications, if used incorrectly in the first trimester of pregnancy, can adversely affect the division of embryonic cells and provoke the development of a mosaic form of this syndrome.
4. Diseases of the reproductive system. Previous infectious diseases affecting the reproductive organs can also affect the division of germ cells.
5. Radiation. The occurrence of genetic mutations may result in irradiation of the genitals with X-rays or any other ionizing radiation. Such external influences are especially dangerous during adolescence, when the most active cell division occurs. The particles that form the radiation penetrate tissue quite easily. If this happens precisely at the moment of cell division, then the risk of a chromosomal mutation is very high.
A child with trisomy 18th chromosome can be born to absolutely any woman, even if both parents are completely healthy and no one in the family has such a pathology.
Frequency
In 60 cases of mutations out of 100, children with the syndrome in question die inside the mother’s abdomen, because the defects are incompatible with life. But the survival rate of children with Edwards syndrome is quite high (slightly lower than that of fetuses with trisomy 21). For every 3-8 thousand babies, one is born with the diagnosis in question.
Doctors say the disease is three times more common among female babies than among boys. There is a high risk of giving birth to a child with these abnormalities in women giving birth who are over 30 years old. During the first 12 months of life, about 90 out of 100 children with this diagnosis die. Boys live on average from 2 to 3 months, and girls about 10 months. The chances that a child with Edwards syndrome will survive into adulthood are slim. Complications of developmental defects become causes of death in children:
- intestinal obstruction
- cardiovascular failure
- pneumonia
- suffocation
Symptoms
Manifestations of the disease are divided into several groups. The first includes those that characterize the appearance of a sick person:
- body weight at birth is approximately 2 kg 100 grams or 2 kg 200 grams
- abnormally developed lower or upper jaw
- the head is small in relation to the whole body
- cleft lip and/or hard palate
- malocclusion and irregular face shape of the child
- rocking foot
- clubfoot from birth
- webbed toes or complete fusion of the toes
- ears set low
- the fingers of the hand are clenched, their placement in the fist is uneven
- the mouth gap is smaller than it should be
The second group of symptoms of the disease concerns the neuropsychic sphere, motor skills and organ function of the sick child:
- umbilical or inguinal hernia
- congenital heart defects, including patent ductus arteriosus, ventricular septal defect, etc.
- smoothing or atrophy of cerebral convolutions
- underdevelopment of the cerebellum, corpus callosum
- mental retardation
- delayed neuropsychic development of a child
- violation of intestinal location
- Meckel's diverticulum
- atresia of the esophagus or anus
- disturbance of the swallowing and sucking reflex
- GERD
- duplication of ureters
- horseshoe-shaped or segmented bud
- underdevelopment of the ovaries in girls
- hypertrophied clitoris in female infants
- hypospadias in male infants
- cryptorchidism in sick boys
- amyotrophy
- scoliosis
- strabismus
Diagnostics
You can most often find out about genetic pathologies while a woman is still carrying a child. This also applies to trisomies. Pregnancy screening is carried out from the 11th to the 13th week. The woman takes blood tests (biochemistry) and an ultrasound is performed. Diagnosis also involves determining the karotype of the embryo if the woman is at risk (complicated family history, infectious diseases in the first trimester, etc.).
During the first semester screening, the amount of human chorionic hormone and plasma protein A associated with pregnancy is determined in the blood. Then they take into account the age of the pregnant woman to find out what her risk is of having a child with trisomy 18.
If a woman is classified as a risk group, a fetal biopsy is performed a little later in order to know for sure whether the child will be born with abnormalities or healthy. From 8 to 12 weeks, chorionic villus sampling is taken. From the 14th to the 18th week, the waters surrounding the fetus are studied. After the 20th week, cordocentesis can be done. The procedure involves taking blood from the umbilical cord (ultrasound is used in the process to control the collection of material).
The number of chromosomes is detected in the material. The CP-PCR method helps with this. If the pregnant woman fails genetic screening for late gestation, a preliminary diagnosis of the genetic mutation is made using ultrasound. In the second and third trimester, there are signs that indicate that the child is likely to be born with trisomy:
- cleft lip
- low-set fetal ears
- microcephaly
- cleft palate
- defects of the musculoskeletal system
- malformations of the genitourinary system
- heart and vascular defects
How to take the Prenetix test?
To take the Prenetix test, you need to apply for the test and donate blood. Blood sampling for testing can be done in any region of the country - in specialized medical institutions or laboratories that have an agreement with CGRM Genetico. Next, the material will be sent for analysis to the Moscow Genetico laboratory. After 12 days you will be able to get the result.
For more detailed information and to sign up for analysis, contact our specialists at the indicated telephone numbers or through the online form on the website.
Diagnosis after birth
Edwards syndrome in newborns is detected by the following signs:
- low birth weight
- microcephaly
- cleft palate or cleft lip
- transverse palmar groove
- undeveloped distal flexion fold on the fingers
- distal location of the axial triradius and increase in ridge count on the palm
- arches on the fingertips
But these signs do not yet indicate that the child has Edwards syndrome. The diagnosis needs confirmation. To do this, the above-mentioned CP-polyplasma chain reaction method is used to determine caropine in a newborn. Ultrasound shows choroid plexus cysts in an infant.
Diagnosis by ultrasound before birth
The following indirect signs of the disease are detected, starting from the twelfth week of gestation:
- 1 rather than 2 umbilical arteries
- The nasal bones are not visualized on ultrasound
- abdominal hernia
- low heart rate
- choroid plexus cysts
Cysts are not dangerous for the baby; they are eliminated by the 26th week of gestation. But such cysts indicate that the child has a genetic developmental abnormality. This may be the syndrome discussed in this article. Cysts are found in a third of patients with this diagnosis. If the doctor sees cysts on an ultrasound, then the next stage of prenatal diagnosis is a consultation with a geneticist.
Classification
Complete trisomy - if a whole additional chromosome appeared at the stage of one cell, then the set of chromosomes is disrupted in each cell of the fetus. With this form, the child has numerous developmental defects that are incompatible with life. This is the most severe version of the disease.
Partial trisomy is diagnosed if an extra chromosome does not appear at the earliest stages of fetal development. In this case, a violation of the genetic makeup is not observed in all cells, and some of them will remain healthy.
Treatment of Edwards syndrome
The goal of therapy: to correct developmental defects that are life-threatening to the child. But it is worth remembering that the child may have serious disabilities and is unlikely to survive beyond 12 months of age. If pneumonia is detected, the baby is given anti-inflammatory drugs and antibiotics. If it is discovered that the baby does not have a sucking and swallowing reflex, then he is fed using a tube. If anal or intestinal atresia is detected in a patient, the passage of food must be restored.
If the doctor sees that the course of Edwards syndrome is favorable, then surgery must be performed to eliminate the umbilical hernia, inguinal hernia, heart defects, and cleft palate. Some symptoms can be relieved by taking medications. For example, if a baby is constipated, he or she will need certain laxative medications. When gases accumulate in the intestines, drugs from a number of “defoamers” are prescribed.
Children who have been diagnosed with the trisomy in question are at risk for the following diseases:
- genitourinary infections
- sinusitis and sinusitis
- arterial hypertension
- apnea
- pulmonary hypertension
- pneumonia
- kidney cancer
- otitis media
It is important to detect these diseases in a baby in time and treat them correctly. The prognosis in most cases of the disease is unfavorable. As already noted, a child has an extremely low chance of surviving to puberty. If the child survives, he will need constant care and supervision because his brain will not be sufficiently developed. Some patients can eat without the help of others, smile and acquire minimal skills.
Prevention
Speaking about the prevention of the disease, it should be noted that the risk of its development in the unborn child always exists. But it still increases in parents after 40 years of age.
Therefore, it is very important for a pregnant woman to follow all the instructions of the gynecologist observing her and undergo an antenatal screening procedure for the timely detection of pathologies.
If one of the spouses has an unfavorable family history, then at the pregnancy planning stage you should definitely visit a genetic specialist and follow all his advice.
