Why does it occur
Normally, a person receives one chromosome of each pair from his mother and father. In Edwards syndrome, the eighteenth chromosome is represented three times. The reason is the nondisjunction of chromosomes during the formation of an egg or sperm, or less often an error in the divisions of an already fertilized cell. Such a mistake is random and does not depend on lifestyle, nutrition, past infections or parental behavior, so there is no need to blame yourself. The likelihood increases with maternal age. There is also a translocation variant, in which a fragment of a chromosome is attached to another, in which case one of the parents may have a balanced rearrangement.
- Full trisomy 18 - most cases
- Mosaic form, when not all cells have an extra chromosome
- Translocation variant with chromosome rearrangement
- Random error in germ cell division
- Risk increases with maternal age
- Not related to the lifestyle and behavior of parents
Signs in a child
Babies are born with low birth weight even in full-term pregnancies. Noteworthy are the structural features of the skull and face: small chin, narrow forehead, low-lying deformed ears, short neck. The position of the hands is very characteristic: the fingers are clenched into a fist, the index and little fingers overlap the rest. The feet have convex soles. There are almost always heart defects, often anomalies of the kidneys, digestive tract and brain. There is a pronounced decrease in muscle tone at birth, followed by increased muscle tone, difficulty feeding and respiratory arrest.
- Low birth weight
- Small chin and narrow forehead
- Low set deformed ears
- Characteristically clenched crossed fingers
- Rocker foot with convex sole
- Defects of the heart and large vessels
- Abnormalities of the kidneys and digestive tract
- Difficulty feeding, respiratory arrest
How is it detected during pregnancy?
The first stage is a combined screening of the first trimester: ultrasound measurement of nuchal translucency thickness and maternal blood testing for PAPP-A and free hCG beta subunit. Trisomy 18 is characterized by a noticeable decrease in both biochemical parameters. The program calculates individual risk, and this is precisely a probability, not a diagnosis. Ultrasound of the second trimester reveals fetal growth restriction, heart defects, choroid plexus cysts, and hand anomalies. A non-invasive prenatal test using the mother’s blood helps clarify the situation, and the final answer is provided by the study of fetal cells.
- Combined first trimester screening
- PAPP-A and free beta-hCG in maternal blood
- Ultrasound with assessment of the nuchal translucency
- Detailed ultrasound of the fetus in the second trimester
- Echocardiography of the fetus for suspected heart disease
- Non-invasive prenatal DNA test
- Amniocentesis or chorionic villus sampling for confirmation
Diagnosis confirmation
A reliable diagnosis is made only by chromosome analysis. During pregnancy, the material is obtained through chorionic villus sampling or amniocentesis; after birth, a sample of the baby’s blood is sufficient. Karyotyping shows the number and structure of chromosomes and allows you to distinguish complete trisomy from mosaic and translocation forms - this is important, because with translocation, parents need to be examined and assess the risk for future pregnancies. A geneticist explains the result, prognosis and family planning options. The decision on further pregnancy tactics is made only by the woman herself after being fully informed.
- Karyotyping of fetal or child cells
- Chorionic villus sampling in the first trimester
- Amniocentesis in the second trimester
- Molecular Methods for Fast Answers
- Karyotyping of parents during translocation
- Consultation with a geneticist with re-risk assessment
Help for the child and family
It is impossible to cure a chromosomal abnormality, so help is aimed at alleviating the condition and supporting the family. The scope of medical interventions is discussed individually: some children need tube feeding, breathing support, treatment of seizures and infections. The issue of surgical correction of a heart defect is decided by a council, taking into account the condition of the child and the opinion of the parents. Palliative care plays an important role, aimed at the baby’s comfort and pain relief. The family needs psychological support, and before planning the next pregnancy, consultation with a geneticist.
- Palliative care and pain management
- Tube feeding with weak sucking
- Treatment of infections and seizures
- Individual decision about cardiac surgery
- Psychological support for family
- Consultation with a geneticist before your next pregnancy