Summary about Disease
Trisomy 18, also known as Edwards syndrome, is a genetic disorder caused by the presence of a third copy of all or part of chromosome 18. This extra genetic material disrupts normal development, leading to a wide range of congenital disabilities and medical problems. It is a severe condition with a low survival rate, with most affected pregnancies resulting in miscarriage or stillbirth. Infants born with Trisomy 18 often have significant health challenges and a shortened lifespan.
Symptoms
Symptoms of Trisomy 18 vary widely, but common features include:
Physical: Low birth weight, small head (microcephaly), distinctive facial features (small jaw, low-set ears), clenched fists with overlapping fingers, rocker-bottom feet, heart defects, kidney abnormalities, omphalocele (abdominal organs outside the body), and cleft lip/palate.
Developmental: Severe intellectual disability, developmental delays, and growth deficiency.
Other: Feeding difficulties, breathing problems, and increased susceptibility to infections.
Causes
Trisomy 18 is caused by a chromosomal abnormality. Most commonly, it occurs due to nondisjunction during the formation of sperm or egg cells, resulting in an embryo with three copies of chromosome 18 instead of the usual two. Less frequently, it can be caused by mosaicism (where only some cells have the extra chromosome) or a partial trisomy (where only a segment of chromosome 18 is duplicated). The risk of Trisomy 18 increases with maternal age, but it can occur in pregnancies of women of any age.
Medicine Used
There is no cure for Trisomy 18, and medical treatment focuses on managing the symptoms and complications. Medications may be used to address specific problems such as:
Heart defects: Medications to manage heart failure or arrhythmias.
Infections: Antibiotics to treat bacterial infections.
Seizures: Anticonvulsant medications.
Pain Management: Analgesics for comfort.
Respiratory Support: Oxygen therapy, ventilator.
Is Communicable
Trisomy 18 is not communicable. It is a genetic disorder caused by a chromosomal abnormality and cannot be spread from person to person.
Precautions
Since Trisomy 18 is a genetic condition, there are no specific precautions to prevent its occurrence in a pregnancy, other than being aware of the increased risk with advancing maternal age. Genetic counseling and prenatal testing can help identify the condition during pregnancy. Once a child is born with Trisomy 18, precautions focus on managing their health challenges and preventing complications, such as infections.
How long does an outbreak last?
Trisomy 18 is not an infectious disease and therefore does not have outbreaks. This question is not applicable to this condition.
How is it diagnosed?
Trisomy 18 can be diagnosed during pregnancy through:
Prenatal Screening Tests: These tests, such as the nuchal translucency scan, combined with blood tests, can assess the risk of chromosomal abnormalities.
Diagnostic Tests:
Amniocentesis: A sample of amniotic fluid is taken for chromosome analysis.
Chorionic Villus Sampling (CVS): A sample of placental tissue is taken for chromosome analysis. After birth, Trisomy 18 is diagnosed based on physical examination, characteristic features, and chromosome analysis (karyotype) of a blood sample.
Timeline of Symptoms
Prenatal: Detection through prenatal screening or diagnostic testing.
At Birth: Low birth weight, distinctive facial features, congenital heart defects, and other physical abnormalities are immediately apparent.
Infancy: Feeding difficulties, breathing problems, developmental delays, and increased susceptibility to infections become evident.
Childhood: Severe intellectual disability, growth deficiency, and ongoing medical complications continue throughout the child's life.
Important Considerations
Prognosis: Trisomy 18 has a poor prognosis, with most infants dying within the first year of life.
Ethical Considerations: Decisions regarding medical interventions and life support should be made in consultation with the medical team and family, considering the child's quality of life.
Support Services: Families of children with Trisomy 18 need significant emotional, practical, and medical support. Support groups and specialized healthcare providers can provide valuable assistance.
Genetic Counseling: It is important for families with a child with Trisomy 18 to seek genetic counseling to understand the risk of recurrence in future pregnancies.