BACKGROUND:

Prenatal diagnosis of double trisomy is rare, particular uncommon simultaneous occurrence of double trisomy involving chromosomes 18 and X.

CLINICAL CASE:

A 43-year-old patient, with a gyneco-obstetric history of four pregnancies and three deliveries, sent from her health center during the fourth pregnancy. Upon admission to the Women's Hospital, the ultrasound study reported a pregnancy of 24.3 weeks of gestation, with a single fetus, clinodactyly, right pelvic member with equinus varus foot, probable esophageal atresia (absence of gastric chamber, polyhydramnios), and umbilical cord. with a single artery. The diagnosis of double trisomy (48XXX +18) was established by cytogenetic study in amniotic fluid. In the week 34, she went to the Emergency Department with labor in the expulsive period and absence of fetal vitality. The couple did not accept the anatomopathological study.

CONCLUSION:

Prenatal diagnosis of double trisomy is rare in the second trimester of pregnancy, its detection is important because it provides valuable information to establish the fetal prognosis and provide adequate genetic counseling. This case is relevant because it is probably the first documented in Mexico and the fifth internationally diagnosed prenatally by cytogenetic study.