Trisomy 12p Syndrome Presenting with Fetal Growth Restriction and Polyhydramnios

A 39-year-old nulliparous woman was referred at 36+6 weeks gestational age, and a prenatal fetal ultrasonography examination found fetal growth restriction (2,190 g <5%), polyhydramnios (amniotic fluid index: 31.76 cm), and absent end-diastolic flow in the umbilical artery. A male baby was born, and fetal dysmorphism including round face, long philtrum, low-set ears, chest retraction, edematous hands and feet, and a simian line on both hands were identified. He was diagnosed with trisomy 12p [der(18)t(12;18)(p11.2;p11.31)] by chromosomal study. The father’s chromosomes appeared normal; however, the mother’s chromosomes had a balanced translocation identified as t(12;18)(p11.2;p11.31). Patent ductus arteriosus, germinal matrix hemorrhage, and hemivertebrae were diagnosed, and respiratory distress, hyperinsulinemic hypoglycemia, and hypothyroidism were also detected. The combination of fetal growth restriction and polyhydramnios may be a significant sign of chromosomal abnormalities, and targeted sonography and a chromosomal analysis should be offered prenatally in such cases.