Edward syndrome is also known as Trisomy 18. It is the second most common trisomy behind trisomy 21 which is the Down Syndrome.
It is a chromosomal abnormality caused by the presence of an extra chromosome 18. This is similar to Down syndrome.
This abnormality is seen commonly with increasing maternal age. Chromosomes are the threadlike structures in cells that hold the gene.
Genes carry the instructions needed to make every part of a baby’s body.
Babies born with Edward’s syndrome have unique features which include kidney abnormalities, developmental delay, limb and also heart abnormalities.
When an egg and sperm join and form an embryo, their chromosomes combine. Each baby gets 23 chromosomes from the mother’s egg and 23 chromosomes from the father’s sperm which makes it 46 in total.
Sometimes the mother’s egg or the father’s sperm contains the wrong number of chromosomes. As the sperm and the egg combine, this mistake is passed on to the baby.
Twenty-nine out of these thirty babies die before their first year birthday.
The Edward syndrome is named after the British geneticists and physician named John Edwards who discovered the extra chromosome in 1960.
Types of trisomy 18:
Partial trisomy 18:
In this type, the child has only part of an extra chromosome 18. That extra part may be attached to another chromosome in the egg or sperm. This type of Edward syndrome is not common.
Full trisomy 18:
In this type, every cell of the child’s body has the extra chromosome. This is the most common type of Edward’s syndrome.
Mosaic trisomy 18:
In this type, the extra chromosome 18 is just in some of the child’s cell. This type of Edward’s syndrome is also not very common.
Symptoms of Edward’s Syndrome
Children with Edward’s syndrome are often times very small when they are born. Most of then do not even survive to birth.
For the ones that survived they have different health problems, abnormalities and physical defect which include;
- Chest deformity
- Slow growth
- Feeding problems
- Microcephaly(small head)
- Serious developmental delays
- Small fingernails
- Heart defects
- Cleft palate or lip
- Weak cry
- Small jaw
- Low set ears
- Hands are often clenched into first
- Dripping of the upper eyelid
- Short breast bone
- Club foot or rocker bottom feet
Causes of Edward Syndrome
Edward syndrome is caused by the presence of an extra chromosome 18.
Most times the extra chromosome 18 is of maternal origin and includes the entire chromosome in most cases other than just a part of the chromosome.
Trisomy is caused by a genetic error in which three copies of a chromosome instead of two are inherited from parents.
Diagnosis for Edward Syndrome
Most times cells are taken from the placenta to analyze their chromosome. CVS(chorionic villi sampling) is also a genetic-based test that can diagnose Edward syndrome.
A woman who is pregnant with a baby that has Edward’s syndrome might have a large uterus. This is very uncommon during pregnancy because of the presence of extra amniotic fluid.
Pregnancy screening during the first and second trimesters including serum markers with ultrasound can accurately diagnose more than three-quarters of all cases.
After birth, if the doctor also suspects that the baby has the Edward syndrome based on the face and body, he may recommend taking a blood test to check for the chromosome abnormality.
To avoid postnatal death, the diagnosis of Edward syndrome is very important.
You can also see a genetic counsellor if you have had a baby with the Edward syndrome and you are scared of having another one because of the syndrome.
Treatment of the Edward Syndrome
The treatment of children with Edwards syndrome is based on the severity of findings.
There is no particular treatment for children with these Chromosomal abnormalities.
Also, there are issues surrounding the management of these babies due to the high mortality rate and difficulty in predicting which babies will live beyond their first year of life.
The major cause of death in many cases is sudden death due to cardiac failure, neurological instability and respiratory failure.
For those infants diagnosed with incomplete Edward syndrome or mosaic trisomy 18, management is focused on addressing abnormalities present since they have such a variable prognosis.
Outlook for Babies with Edward’s Syndrome
Since Edward syndrome has serious physical defects, most babies with the condition do not survive until birth. Almost half of the babies who are carried full time are stillborn.
Male babies with Edward syndrome are more likely to be stillborn than female babies. Research indicates that
- 60% to 75% of babies survive for 24 hours,
- 20% to 60% of babies survive for 1 week,
- 22% to 44% survive for 1 month,
- 9% to 18% manage for 6 months, and
- 5 per cent to 10 per cent for over 1 year.
It means there are few affected children left who require ongoing screening during their lives.
Having a child with Edward syndrome can most times be emotionally difficult and it is important for parents to get support during this tough time.
Specialists who are in pediatric development, neurology, and genetics are most times helpful in guiding the ongoing care of these children.
The Trisomy 18 foundation can also provide great support.