We present first-trimester application of expanded non-invasive prenatal testing (NIPT) in the genetic investigation of fetal 1p36 deletion syndrome associated with a familial unbalanced reciprocal translocation of 46,XX,der(1)t(1;2) (p36.2;q37.3)dmat. A 37-year-old, gravida 2, para 0, woman underwent expanded NIPT at 13 weeks of gestation because of advanced maternal age and the fear of complications of invasive procedures of prenatal diagnosis. She had experienced one spontaneous abortion. The pregnancy was conceived by in vitro fertilization and embryo transfer (IVF-ET) because of tubal occlusion. NIPT was positive for 1p36 deletion. At 17 weeks of gestation, she underwent amniocentesis but intrauterine fetal death occurred after amniocentesis and the pregnancy was terminated. Amniocentesis revealed a derivative chromosome 1 with an aberrant short arm terminal segment of chromosome 1. Subsequent cytogenetic analysis of parental bloods showed a karyotype of 46,XY in the father and a karyotype of 46,XX,t(1;2) (p36.2;q37.3) in the mother. The karyotype of amniocytes was 46,XX,der(1)t(1;2) (p36.2;q37.3)dmat, consistent with partial monosomy 1p (1p36.2→pter) and partial trisomy 2q (2q37.3→qter). Array comparative genomic hybridization (aCGH) analysis on the DNA extracted from cultured amniocytes revealed the result of arr 1p36.33p36.22 (852,863-11,303,452) × 1.0 and arr 2q37.3 (242,785,405-243,068,396) × 3.0 [GRCh 37] with a 10.451-Mb deletion of 1p36.33-p36.22 encompassing 116 OMIM genes including RERE and a 283-kb duplication of 2q37.3 encompassing one OMIM gene of PDCD1. Expanded NIPT has the advantage of early detection of familial unbalanced reciprocal translocation in the fetus.

Carriers of balanced reciprocal chromosomal translocations are at known reproductive risk for offspring with unbalanced genotypes and resultantly abnormal phenotypes. Once fertilization of a balanced translocation gamete with a normal gamete, the partial monosomy or partial trisomy embryo will undergo abortion, fetal arrest or fetal malformations. We reported a woman with chromosomal balanced translocation who had two adverse pregnancies. Prenatal diagnosis was made for her third pregnancy to provide genetic counseling and guide her fertility. We presented a woman with chromosomal balanced translocation who had three adverse pregnancies. Routine G banding and CNV-seq were used to analyze the chromosome karyotypes and copy number variants of amniotic fluid cells and peripheral blood. The karyotype of the woman was 46,XX,t(4;5)(q33;p15). During her first pregnancy, odinopoeia was performed due to fetal edema and abdominal fluid. The umbilical cord tissue of the fetus was examined by CNV-seq. The results showed a genomic gain of 24.18 Mb at 4q32.3-q35.2 and a genomic deletion of 10.84 Mb at 5p15.2-p15.33 and 2.36 Mb at 15q11.1-q11.2. During her second pregnancy, she did not receive a prenatal diagnosis because a routine prenatal ultrasound examination found no abnormalities. In 2016, she gave birth to a boy. The karyotype the of the boy was 46,XY,der(5)t(4;5)(q33;p15)mat. The results of CNV-seq showed a deletion of short arm of chromosome 5 capturing regions 5p15.2-p15.33, a copy gain of the distal region of chromosome 4 at segment 4q32.3q35.2, a duplication of chromosome 1 at segment 1q41q42.11 and a duplication of chromosome 17 at segment 17p12. During her third pregnancy, she underwent amniocentesis at 17 weeks of gestation. Chromosome karyotype hinted 46,XY,der(5)t(4;5)(q33;p15)mat. Results of CNV-seq showed a deletion of short arm (p) of chromosome 5 at the segment 5p15.2p15.33 and a duplication of the distal region of chromosome 4 at segment 4q32.3q35.2. Chromosomal abnormalities in three pregnancies were inherited from the mother. Preimplantation genetic diagnosis is recommended to prevent the birth of children with chromosomal abnormalities.