MONOZYGOTIC TWINS DISCORDANT FOR MULTIPLE CONGENITAL ANOMALIES

Relevance: The management of a monochorionic multiple pregnancy with abnormal development of one of the fetuses is a clinical and ethical dilemma, since, there is a risk of preterm birth and perinatal death of the second twin regardless of the chosen tactics. Modern molecular genetic methods assist in optimizing the management of pregnant women and newborns in such cases. We present a case report on the management of multiple pregnancy: discordant monozygotic twins with multiple developmental anomalies. Case report: A 40-year-old multigravida presented at 17 weeks gestation to the National Medical Research Centre for Obstetrics, Gynecology and Perinatology, Moscow, to determine the tactics of managing monochorionic twins with large omphalocele and spinal deformity in one of the fetuses. At the first stage of the examination, the patient underwent a separate amniocentesis; normal female molecular karyotype arr(1-22,X)x2 was detected in both fetuses. Impairments in methylation of IC1 (H19) and IC2 (KCNQ1OT1) sites of the critical region of chromosome 11 associated with Beckwith–Wiedemann syndrome were excluded on the basis of DNA of the amniotic fluid in both fetuses. Monozygosity was confirmed by matching samples of the first and second fetuses for five SNP markers on each of 22 pairs of autosomes. Given the normal result of the genetic examination of both fetuses and the potential risks of perinatal complications during intrauterine intervention, the patient refused selective fetocide. An operative delivery was performed at 33 weeks and 5 days due to the repeated increase in polyhydramnios and zero diastolic blood flow in the umbilical cord arteries, according to the ultrasound Doppler assessment. The first healthy girl was born with a body weight of 2140 g, an Apgar score of 7-8 points, and was discharged home in satisfactory condition at the age of 12 days of life. The second girl with multiple developmental anomalies was born with a body weight of 1760 g, an Apgar score of 5-6 points, and died at the age of 2 days 2 hours due to multiple organ failure. Both children had a normal female karyotype (46,XX) which was revealed postnatally, and a whole-exome sequencing of pathogenic and likely pathogenic variants associated with the phenotype was performed. Monozygosity of the twins was confirmed, no accidental findings were detected. Conclusion: The above case demonstrates the principles of modern ante-and perinatal multidisciplinary tactics for multiple pregnancies discordant for structural fetal malformations. © A group of authors, 2023.