Edwards syndrome, also known as trisomy 18, is a rare but serious condition. It is a genetic condition that causes physical growth delays during fetal development
Sadly, most babies with Edwards syndrome will die before or shortly after being born. A small number (about 13 in 100) babies born alive with Edwards’ syndrome will live past their 1st birthday. Children who survive past their first year may face severe intellectual challenges.
Trisomy 18 is the second most common type of trisomy syndrome, after trisomy 21 (Down syndrome). About 1 in every 5,000 babies is born with trisomy 18, and most are female.
Important symptoms of Edwards syndrome (trisomy 18) typically includes –
• Poor growth before and after birth
• Multiple birth defects
• Severe developmental delays or learning problems
▪︎ Symptoms during pregnancy
Your doctor will look for signs of Edwards syndrome (trisomy 18) during a prenatal ultrasound, including:
• Very little fetal activity.
• A single artery in your umbilical cord.
• A small placenta.
• Birth defects.
An Edwards syndrome diagnosis can result in a live birth, but trisomy 18 most often causes a miscarriage during the first three months of pregnancy or the baby is stillborn.
▪︎ Symptoms after birth
After birth of baby, the following physical characteristics of Edwards syndrome (trisomy 18) could be noticed:
• Decreased muscle tone (hypotonia).
• Low-set ears.
• Internal organs forming or functioning differently (heart and lungs).
• Issues with cognitive development (intellectual disabilities), which are typically severe.
• Overlapping fingers and/or clubfeet.
• Small physical size (head, mouth and jaw).
• Weak cry and minimal response to sound.
Normally, a person has 23 pairs of chromosomes. Chromosomes are the packages of genetic information, made of DNA, that contain the instructions the body uses to build a person. Chromosomes come in 23 pairs, with most people having 46 total chromosomes. Trisomy 18 is caused when a person has three copies of chromosome #18 instead of the usual two, for a total of 47 chromosomes. Most frequently it is of maternal origin and includes the entire chromosome in most cases rather than a part of the chromosome.
This extra chromosome affects a baby’s development, resulting in a number of medical issues which may include: heart defects, digestive tract abnormalities, cleft lip, joint contractures (abnormal bending), vision and hearing problems, slow pre- and postnatal growth, seizures, and hypotonia (weak muscles).
• Full Edward’s Syndrome (Three complete sets of the 18th chromosome):
Most severe type of the disease, highest mortality rate. About 95% of cases of Trisomy 18 are this type.
• Mosaic Edward’s Syndrome (Trisomy only appears in some cells): Severity of the condition depends on the number and types of affected cells, some children may live to adulthood. About 5% of cases of Trisomy 18 are this type.
• Partial Edward’s Syndrome (Partial trisomy 18, only sections of the 18th chromosome are tripled):
Severity of the condition depends on which section of the 18th chromosome is tripled. Less than 1% of cases of Trisomy 18 are this type.
Risk Factors –
• The probability of having a baby with Trisomy 18 is higher in older mothers.
• Trisomy 18 can be inherited due to a familial chromosome rearrangement called a translocation.
☆ Trisomy 18 is never the result of anything a mother or father did, or didn’t do.
The side effects of the condition have serious and often life-threatening consequences, including:
• Congenital heart disease and kidney disease (present at birth).
• Breathing abnormalities (respiratory failure).
• Gastrointestinal tract and abdominal wall issues and birth defects.
Most cases of trisomy 18 are diagnosed prenatally. Standard pregnancy screening during the first and second trimesters including serum markers (plasma protein, beta-hCG, alpha-fetoprotein, unconjugated estriol, and inhibin A) with ultrasound (nuchal translucency and other anatomic abnormalities) can accurately diagnose more than three quarters of all cases.
Chorionic villi sampling (CVS) is a genetic-based test that can diagnose trisomy 18. Amniocentesis, is another test which collects a sample of the amniotic fluid from around your baby and help in diagnosis of Trisomy 18.
Both of these are invasive tests increase the risk of miscarriage and need to be thoroughly discussed with the parents.
To diagnose Edward’s Syndrome after birth, a blood sample will be taken and genetically analysed.
This diagnosis of trisomy 18 is important in order to better prepare parents and caregivers due to the high risk of fetal demise and early postnatal death.
There is no possibility to cure for Trisomy 18 and treatment options depend on the severity of the condition. There is no known prenatal treatment that will improve the outcome for a baby with Trisomy 18. Different therapies and medical management will mostly focus on supporting the family and the babies’ acute impairments.
As trisomy 18 causes some serious physical defects, many babies with the condition don’t survive to birth. About half of babies who are carried full-term are stillborn. Boys with trisomy 18 are more likely to be stillborn than girls.
From the babies who do survive, less than 10% live to reach their first birthday. Children who do live past that milestone often have severe health problems that require a large amount of care. Only a very small number of people with this condition live into their 20s or 30s.
Having a child with trisomy 18 can sometimes be emotionally traumatic, and it’s important for parents to get support during this crucial time.
For more informative articles about such genetic disorders and other health related issues, please visit our website www.santripty.com and also feel free to consult.