Trisomy 18 – Definition
Trisomy 18, also called Edwards syndrome, is the second-most common constitutive chromosomal abnormality after Down syndrome.
Synonym:
Edwards syndrome
Gene:
Trisomy 18
Gene product:
Not applicable
Function:
Not applicable
Pattern of inheritance:
Sporadic
Prevalance:
1:6.000 – 1:8.000 live births
Genotype-phenotype correlation:
Children with mosaicism or partial trisomy 18 have a better prognosis.
Penetrance:
As far as known complete
Trisomy 18 – Diagnosis
Diagnosis
The diagnosis is made clinically and confirmed by chromosomal analysis.
Differential Diagnoses
- Other malformation syndromes
Clinical Presentation
Trisomy 18 is characterized by various malformations, growth retardation, developmental delay, and an intellectual disorder. In the first 5 years of life, 90% of those affected die because of heart or kidney abnormalities, eating disorders, infections, or apnea. Hepatoblastomas and Wilms tumors are the most common tumors. The risk of the latter is around 1%.
Special Features of Treatment
Treatment by a multidisciplinary team is necessary.
Diagnosis of Trisomy 18- What's Next?
Once diagnosed, it is recommended that a cancer predisposition specialist manage the patient. The following section explains whether cancer screening tests or other measures are necessary and how they should be performed. Some additional information, including links to support groups, is also included at the end of this page.
Diagnosis of Trisomy 18- What's Next?
Once diagnosed, it is recommended that a cancer predisposition specialist manage the patient. The following section explains whether cancer screening tests or other measures are necessary and how they should be performed. Some additional information, including links to support groups, is also included at the end of this page.
Recommendations for Early Detection in Your Patients
- Early detection of a Wilms tumor with ultrasound, every 3 months until the age of 7
- Early detection of hepatoblastoma with AFP and an abdominal ultrasound, every 3 months until age 4
- Due to the poor prognosis, this is a matter of controversy and is by no means clearly indicated.
