What is Edwards Syndrome (Trisomy 18)

Edwards Syndrome or Trisomy 18 is a rare genetic condition that causes abnormalities in many parts of the body and leads to developmental delays during the growth stage of a fetus. This particular autosomal trisomy syndrome¹ is called Edwards Syndrome after John Hilton Edwards, a professor of genetics at Oxford University, wrote a paper on “A New Trisomic Syndrome” in the 1960s.

Edwards Syndrome Trisomy 18 is one of the children’s most common birth defects. This genetic condition can be seen in approximately 3 in 10,000 births in the UK. The risk of bearing children with Edwards Syndrome increases in women who are over the age of 30. Research has shown that the average maternal age in the USA is 30. Maternal age has said to play a role in increased chances of this syndrome.

A. Edwards Syndrome Or Trisomy 18

Most babies usually inherit 23 chromosomes from each of their parents. However, babies born with Edwards Syndrome Trisomy 18 have an extra copy of the 18th chromosome, possibly due to an extra chromosome in the egg or the sperm of the parents. Studies about the new autosomal trisomy syndrome show multiple congenital anomalies in the affected individuals.

There can be 3 kinds of “Trisomy 18” or “Edwards Syndrome” (presence of an extra chromosome in the baby’s cells) –

1. Full Trisomy 18

Considered one of the most severe cases of genetic disorders ²in live births, a child with full Edwards Syndrome would have a third copy of the 18th chromosome in each of the body’s cells. Unfortunately, most babies born with this trisomic syndrome die before they are born.

2. Partial Trisomy 18

A balanced translocation of a part of the extra chromosome is prominent in the child. This anomaly is present in only 1-in-100 cases. Partial Trisomy 18 is commonly observed in cases where there is an exchange of genetic material between two chromosomes that do not belong to the same pair. A study involving molecular mapping of the Edwards Syndrome Phenotype to two noncontiguous regions on chromosome 18 published in the Am J Hum Genet (American Journal of Human Genetics) initially showed patients with partially duplicated chromosome 18.

3. Mosaic Trisomy 18

Chromosomal abnormality³ is prominent in some, rather than all cells in the body. A series of cells with extra material attached to the chromosome is present in a randomised fashion. A study in the Am J Med Genet or the American Journal Of Medical Genetics presented Two patients with Trisomy 18 mosaicism.

B. Diagnosis for Edwards Syndrome

Although such conditions are detectable during the second-trimester sonography, a more precise form of prenatal diagnosis would be to analyse cells from the amniotic fluid (amniocentesis⁴) or the placenta (chorionic villus sampling)⁵ of the mother. These diagnostic tests are offered only if the screening shows a higher risk of such disorders as they are invasive and may increase the risk of a miscarriage

Women are offered screening to test the chances of genetic conditions such as Edwards Syndrome Trisomy 18, Down Syndrome, Patau Syndrome, etc developing in the baby between 10 to 14 weeks of the pregnancy. This test consists of an ultrasound and a blood test that would measure the fluid present under the skin behind the baby’s neck.

Screening can also take place in the 20th week of the pregnancy which would look for the physical conditions of the baby using an ultrasound. In case a diagnosis is required after birth, doctors take a blood sample from the baby to test for any such conditions.

Increased thickness in the nuchal translucency and lack of cells in the nasal bone may be signs indicating Edwards Syndrome. These results are prominent in the first or second trimester of the pregnancy.

Specialists for Edwards syndrome may include a Medical Geneticist, an Obstetrician, a Maternal-Foetal Medicine Specialist or a Neonatologist depending on the stage of pregnancy and the condition of the baby.

C. Causes of Edwards Syndrome

The most commonly known cause of Edwards Syndrome Trisomy 18 is a change in the egg or the sperm before conception. an extra chromosome is attached to either and gets passed on to the baby.

Another leading cause of Edwards Syndrome⁶ or Trisomy 18 is an increase in the mother’s age at the time of the pregnancy. Women over 30 years of age have a higher probability of having children with such genetic conditions.

Edwards Syndrome (Trisomy 18) is usually not inherited and occurs randomly as the eggs or sperm are formed in the parent’s body. If a parent has a child with Edwards Syndrome Trisomy 18, it is highly unlikely that they have another child with this condition. The chances are said to be no more than 1%.

D. Prevention And Precautions

Since Edwards Syndrome (Trisomy 18) takes place at random in the sperm or the egg, preventative measures can not be determined. Scientific evidence has yet to prove that there is anything to be done by one or the other parent to prevent such anomalies. There is also no reason to believe that either is at fault.

It is recommended that the parents and family members of the child with Edwards Syndrome seek counselling and brace themselves for any possible outcomes. Stress has been proven to be worse for the baby as well as the mother. Therefore, the parents must be provided with a lot of support and understanding from family and friends.

Although there aren’t any proven ways to reduce the risk of genetic issues ⁷and Edwards Syndrome in the foetus, it is recommended that women planning to conceive and pregnant ladies maintain a healthy lifestyle and avoid harmful substances such as alcohol and cigarettes to ensure better health conditions for the baby.

E. Mortality Rates

In most cases, women carrying children with Edwards syndrome Trisomy 18 end up having miscarriages in the first three months of the pregnancy, otherwise the babies are stillborn. The chances of live births surviving for over a year are 13-in-100. Children with Edwards syndrome don’t typically survive till adulthood.

The longest a patient with Edwards Syndrome has lived in the age of 26. She had a recurring history of infections and Ventricular Septal Defect⁸ due to a non-mosaic type of Edwards Syndrome or Trisomy 18.

The chances of survival strongly depend upon the condition of the baby and the care available to her or him. The survival rate may decrease if the baby has delayed organs or a heart condition. The chances of live-birth increase with the gestation age.

Edwards syndrome must be detected early on in the pregnancy so that the doctors may take all necessary steps to ensure survival. Patient education also goes a long way in saving a baby that is suffering from Edwards Syndrome.

F. Symptoms And Effects of Edwards Syndrome Trisomy 18

Though most babies diagnosed with Edwards Syndrome Trisomy 18 die shortly before or after birth, those who survive past the birth stage have a low life expectancy and suffer several health problems. A population-based analysis showed 114 live birth cases with Edwards Syndrome or Trisomy 18 and that 5-10% of the children with the syndrome live past the age of one. The majority of the babies affected are girls.

Edwards syndrome can have serious and life-threatening consequences on the baby and can make her or him prone to infections

Multiple congenital anomalies caused by the presence of an extra chromosome lead to several deformities and congenital malformations in children, such as – low-set ears, overlapping fingers, anomalous or rocker-bottom feet, malformation in the second and third toes, mental defects, etc. Characteristics of a baby who has Edwards Syndrome may include –

1. low birth weight
2. Short breast bone
3. delay in neurological developments
4. intrauterine growth retardation (poor growth of the foetus in the uterus)
5. small jaw and cleft lip
6. clenched fists with deviating or overlapping fingers
7. weak cry
8. joint contractures

(tightening of tissues that cause stiffness and deformity in the joints)

A child with Edwards Syndrome Trisomy 18 runs the risk of developing some severe complications before or after birth that can jeopardise her or his survival, such as –

1. scoliosis
2. learning disability
3. Wilms tumor
4. gastrointestinal issues
5. respiratory failure
6. atrial septal defect or other heart defects

G. Treatment

The treatment for Edwards syndrome varies based on the severity of the disease. There is no definitive “cure” but doctors will try to help the baby manage her or his symptoms best they can.

The procedure followed for the management of this condition also depends on the type of chromosomal abnormality which is found in the child. whether it is full, partial, or mosaic would help in determining what issues might be most prevalent in the child and what the area of focus will be.

Most babies with partial trisomy or mosaic trisomy will be prone to having serious complications in vital organs or other developmental issues that need to be dealt with first and foremost.

A lot of ethical issues can surround the treatment and care of a baby with Edwards Syndrome. The doctors are expected to act with utmost professionalism and sensitivity. Priority would be to reduce the symptoms of the baby and deal with any heart or respiratory defects she or he may have.

The baby would also need to be kept under observation post-delivery and might require supportive medical care for respiration and nutrition. As a baby with Edwards syndrome would grow, she or he would require assistance from various specialists to be able to thrive.

H. Patient Education And Management Tools

Parents of a baby with Edwards syndrome often have to make difficult decisions about treatment options. They must be educated about the syndrome and its effects and complications. Doctors should be sure to give as much information to the parents as possible and that this information is legitimate and relevant to their baby’s condition.

Managing symptoms of Edwards Syndrome may go a long way in ensuring a longer lifespan for the baby. It may be crucial to admit babies with such conditions to be admitted into the NICU (especially in case of serious complications such as heart disease) and that they are given all the support required to survive. Pregnant women with this diagnosis must be closely monitored throughout their term so that any issues that may arrive can be dealt with immediately and efficiently.

It is recommended that the parents seek counselling to grasp the risks and options available to them. This would help them in making informed decisions about the future of their child. A plan should be formulated among the parents and the doctors about the delivery, care and treatment of the baby before and after birth. The doctor must only give realistic hopes to the parents and deviate from being judgemental over any choices the parents might make.

I. Other Genetic Disorders

There are over 6,000 genetic diseases and DNA abnormalities. With the help of non-invasive prenatal testing, screening tests and diagnostic tests lots of research has been conducted in this field. This research has been helpful in the treatment and diagnosis of those who suffer from such conditions. Some examples of rare genetic disorders like Edwards Syndrome include – down syndrome, Angelman syndrome, and trisomy 13.

Children born with Down Syndrome inherit an extra copy of the 21st chromosome from either parent. Similar to Edwards Syndrome Trisomy 18, also causes intellectual and physiological problems due to developmental delays in the body. It is usually detectable by the 12th week of the pregnancy. Babies afflicted with this condition tend to have a higher probability of developing Alzheimer’s or epilepsy. However, a child with Trisomy 21 may live much longer than a child with Edwards Syndrome (their expectancy would be over the age of 60).

Angelman Syndrome causes nerve-related symptoms and seizures in children. Patients with this syndrome have difficulty walking with balance and lack coordination. Even though they have a near-normal life expectancy, they require psychosocial support throughout their lives. A child usually develops this syndrome due to a missing or malfunctioning gene UBE3A⁹ from the mother. Due to the inactivity of this gene, there are several delays in the development of the body and mind of the baby. Babies with this condition often have a buoyant demeanour. They also tend to have a speech impairment.

Trisomy 13 or Patau Syndrome is a rare form of the genetic condition where the child can not live past his first week. They have episodes of no breathing and severe health issues. They also have a small head and microphthalmia (underdeveloped eyes which may cause blindness or vision problems). Based on the condition of the patient, the doctor may suggest either surgery or therapy as a method of treatment. The area of focus would mainly be controlling the symptoms and minimising the baby’s discomfort.

Children who are diagnosed with such disorders often have to get admitted into a neonatal intensive care unit after delivery. This can be very stressful for the parents. Most babies with Edward Syndrome Trisomy 18 or Patau Syndrome Trisomy 13 ¹⁰need a feeding tube to receive the necessary nutrition. Some genetic conditions can be corrected by providing cells with new DNA and using gene therapy. Others, however, may not have any known cures. Research must be conducted on such conditions so that babies can live healthy and full lives.

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Last Updated on February 3, 2024 by ayeshayusuf