OBJECTIVE: Evaluation of sonographic findings and management of trisomy 18
METHOD: Case report
CASE: A 26-year-old woman, gravida 2, para 1, with no history of comorbidities was referred to our perinatology department for a 22-weeks pregnancy with multiple fetal anomalies. She had no prenatal screening tests and no known familial genetic disorder or consanguinity. Sonographic examination revealed an omphalocele (containing part of the fetal liver), bilateral large choroid plexus cysts and triventriculomegaly, clenched hands, postaxial polydactyly, a transitional type atrio-ventricular septal defect (AVSD) (Figure 1). The couple was informed and counseled about the prognosis, prenatal diagnostic tests, and treatment and gave written consent for amniocentesis and termination of pregnancy (TOP). Since the sonographic findings indicated trisomy 18, a fatal congenital anomaly, the TOP was performed shortly after quantitative fluorescent polymerase chain reaction (QF-PCR) and conventional fetal karyotyping by amniocentesis. Macroscopic examination after abortion confirmed an omphalocele, postaxial polydactyly of the hands, and clenched hands (Figure 2). QF-PCR and fetal karyotyping revealed a karyotype of 47, XY +18.
CONCLUSION: Trisomy 18, also called Edwards syndrome, is one of the most common aneuploidies after trisomy 21 and 13, and can be detected by prenatal screening tests. While a significant proportion of fetuses with trisomy 21 do not have ultrasound findings, almost all cases with trisomy 18 may have one or more detectable structural abnormalities. Even if pregnant women do not have a prenatal screening test, trisomy 18 can be diagnosed early in pregnancy using sonography and TOP can be performed before the limit of viability, which begins at 24 weeks gestational age.
Anahtar Kelimeler: Trisomy 18, Edwards Syndrome, Ultrasound, Pregnancy termination