Definition

Trisomy 18, also called Edwards syndrome, is the second-most common constitutive chromosomal abnormality after Down syndrome.

Key Data
Diagnosis
Differential Diagnoses
Clinical Presentation
Therapeutic Considerations
Surveillance Recommendations
Additional Information

Key Data

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Synonym	Edwards syndrome
Gene	Trisomy 18
Gene product	Not applicable
Function	Not applicable
Heredity	Sporadic
Prevalence	1:6.000-1:8.000 live births
Genotype-phenotype correlation	Children with mosaicism or partial trisomy 18 have a better prognosis.
Penetrance	Complete as far as is known

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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%.

Therapeutic Considerations

Treatment by a multidisciplinary team is necessary.

Surveillance Recommendations

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.