Sonographic findings in partial type of trisomy 18

ABSTRACT

Trisomy 18 [Edwards syndrome] is the second most common trisomy among live born fetuses, with poor prognosis. Estimate of its incidence is between 1 in 4000- 16000 live births. Most of the chromosomal abnormalities in fetuses are detected by prenatal ultrasound findings in the first and second trimesters. In this case report, we present a partial type of trisomy 18 occurring through de novo unbalanced translocation of chromosomes 18 and 21. The ultrasound features enabling the early detection of trisomy 18 include a delayed ossification of calvarium combined with early onset of fetal growth restriction [FGR] and the absence of nasal bone through performing triple test followed by amniocentesis. Finally, the parents decided to terminate the pregnancy