Edwards syndrome (chromosome 18 trisomy syndrome): causes, symptoms, diagnosis, treatment

Edwards syndrome (trisomy 18, trisomy 18) is caused by an extra chromosome 18 and typically involves low intelligence, low birth weight, and multiple birth defects, including severe microcephaly, prominent occiput, low-set, malformed ears, and characteristic facial features.

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Epidemiology

Trisomy 18 occurs in 1/6000 live births, but spontaneous abortions are common. More than 95% of children have complete trisomy 18. The extra chromosome is almost always inherited by the child from the mother, and the risk increases with the mother's age. The ratio of girls to boys is 3:1. Children with Edwards syndrome are more often born to women over 35 years of age. The probability of having a child with trisomy 18 again in a family does not exceed 1%, which is not a contraindication for repeated childbearing.

Causes Edwards syndrome

The causes of Edwards syndrome are related to errors in the formation of genetic information during conception. The main causes include:

1. Abnormal chromosome segregation: Edwards syndrome usually results from errors during meiosis, the process by which genetic material (chromosomes) is separated in cells before conception. In this case, an extra copy of chromosome 18 usually occurs during the formation of gametes (sperm and egg).
2. Abnormal chromosome fusion: Sometimes errors occur in which two chromosome 18s combine into one, which can also lead to Edwards syndrome.
3. Mosaicism: Sometimes this syndrome can occur due to mosaicism, where some cells in the body have a normal number of chromosomes and others have an extra copy of chromosome 18. This can affect the severity of symptoms and how the syndrome appears.

Edwards syndrome most often occurs randomly and is not hereditary. It is a rare genetic disorder and is often associated with severe medical problems.

Symptoms Edwards syndrome

The pregnancy history often includes poor fetal motility, polyhydramnios, a small placenta, and a single umbilical artery. The baby is small for gestational age, with hypotonia and severe skeletal muscle hypoplasia and low subcutaneous fat. The cry is weak, and the response to sounds is reduced. The orbital rims are hypoplastic, the palpebral slits are short, and the mouth and jaw are small, giving the face a narrowed (pointed) appearance. Microcephaly, a prominent occiput, low-set malformed ears, a narrow pelvis, and a short sternum are common. A characteristic hand is often noted - clenched into a fist with the index finger positioned above the third and fourth fingers. The distal fold on the little finger is often absent, and the number of arches on the fingertips is reduced. The toes are hypoplastic, the big toe is shortened and often dorsiflexed. Clubfoot and rocker foot are common. Severe congenital heart defects, especially patent ductus arteriosus and ventricular septal defects, are common, as are malformations of the lungs, diaphragm, gastrointestinal tract, abdominal wall, kidneys and ureters. Hernias and/or diastasis recti, cryptorchidism and excess skin that forms folds (especially along the back of the neck) are also common.

Edwards syndrome, or trisomy 18, is characterized by a combination of intrauterine growth retardation and polyhydramnios. Of the congenital malformations, the most common are neural tube defects (spinal hernia, congenital hydrocephalus) and reduction defects of the limbs. The facial phenotype is specific with small facial features (short eye slits, microstomia, microgenia) and elongated auricles. Characteristic dermatoglyphics (the presence of 5 or more arcs on the fingertips). Patients diagnosed with Edwards syndrome have profound mental retardation and high mortality - no more than 10% of children survive to 1 year.

Forms

The symptoms and forms of Edwards syndrome can vary greatly from one person to another. Some of the main forms and symptoms of Edwards syndrome are listed below:

1. Classic form (full trisomy 18):

   • Delayed psychomotor development.
   • Mental retardation.
   • Microcephaly (small head).
   • Deformities of the skeleton and limbs (clinodactyly, soleus, osteoarthritis).
   • Scoliosis (torticollis).
   • Short stature.
   • Microphthalmia (small eyes) and other eye abnormalities.
   • Cardiac defects (eg, atrioventricular defect, arterial hypertension).
   • Problems with breathing and digestion.
   • Increased risk of reflux (return of stomach contents into the esophagus).
   • Kidney problems.
   • Low muscle tone.

2. Mosaic form (mosaic with trisomy 18):

   • Some children with Edwards syndrome may have a mosaic pattern, where only some cells in the body have an extra copy of chromosome 18. This may result in milder symptoms and a better prognosis.

3. Other forms:

   • In rare cases, Edwards syndrome may present in more atypical or less severe forms, making it more difficult to diagnose.

Edwards syndrome is usually associated with serious medical problems.

Diagnostics Edwards syndrome

The diagnosis can be suggested prenatally by malformations detected by ultrasound of the fetus or screening examination of the mother, and postnatally by characteristic appearance. Confirmation in both cases is carried out by karyotype examination. Karyotyping should also be performed in the presence of intrauterine growth retardation, multiple congenital malformations and corresponding results of screening examination of the mother.

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Treatment Edwards syndrome

Treatment is aimed at relieving symptoms and improving the quality of life of patients, as this syndrome is often accompanied by serious medical problems. It is important to note that Edwards syndrome is usually associated with a limited life expectancy, and the goal of treatment is to provide comfort and support to patients.

Treatment for Edwards syndrome may include the following aspects:

1. Medical support: Children often require intensive medical care. This may include surgery to repair heart defects, treatment for breathing problems, treatment for digestive problems, and skin care.
2. Care and rehabilitation: Special attention is given to the care of the child. Physical therapy, orthopedic rehabilitation and other types of therapy can help improve motor skills and overall functioning.
3. Symptom management: Symptoms such as low muscle tone, cramps, and reflux may require medication. It is important that treatment is done under medical supervision.
4. Specialized Medical Team: Treatment typically involves a team of specialists, such as pediatricians, geneticists, cardiologists, orthopedists, and others, depending on the patient's specific needs.
5. Psychological support: Edwards syndrome can have an emotional and psychological impact on a family. Psychological support or counseling can be helpful for families dealing with this syndrome.
6. Palliative care: In some cases, especially if the patient's condition is too severe, a decision is made about palliative care aimed at ensuring comfort and quality of life.

Forecast

More than 50% of children die within the first week; less than 10% survive to one year. There is a marked delay in development.