The pattern of chromosomal abnormalities in recurrent miscarriages: a single center retrospective study

Molecular cytogenetic study of the fetal genome in idiopathic recurrent pregnancy loss

OBJECTIVE

Despite numerous studies on the causes of recurrent pregnancy loss (RPL), nearly half of cases remain unidentified, which determines the research relevance. This study aims to investigate microchromosomal variations in the fetal genome associated with the development of idiopathic RPL.

METHODS

The research was supported by the Centre for Molecular Medicine and the Research Institute of Obstetrics, Gynecology and Perinatology and conducted over a period of 2 years. The study employed the Prepito automatic analyzer from PerkinElmer and the ChemagicPrepito nucleic acid extraction system, to isolate 100 DNA samples from conception products of women with idiopathic RPL, and, subsequently, to analyze for the presence of full-genome chromosomal abnormalities by array comparative genomic hybridisation (aCGH) using CGX-HD microarrays (8x60K), Format 1: CGX (80x60K), a ScanRI microarray scanner (PerkinElmer, Finland), and Genoglyphix, Cytogenomix software.

RESULTS

The study determined that 83% of the materials studied had a normal molecular karyotype, while unbalanced chromosomal abnormalities were detected in 17% of cases, of which 35.3% of abortions had aneuploidies and 64.7% had various structural abnormalities. Among the aneuploidies, 66.7% were trisomies and 33.3% were monosomies. In the group of structural disorders, 81.8% were microdeletions, while microduplications accounted for 18.2%. The data obtained on the frequency and structure of chromosomal abnormalities detected in abortions in the sample surveyed showed that idiopathic RPL is not caused by chromosomal abnormalities of embryos and, unlike all other forms of RPL, has a different cause not related to chromosomal abnormalities.

CONCLUSION

This study conducted molecular cytogenetic analysis of the fetal genome related to RPL. Its findings can help optimize the process of counseling patients with idiopathic RPL.

Homozygosity for Robertsonian Translocation (14q;15q) in a Newborn with a Familial History of Recurrent Abortion and Newborns Affected by Hepatosplenomegaly: A Case Report

Background

Robertsonian translocations (RobTs) are one of the major chromosomal abnormalities which lead to spontaneous abortion. They occur in the human population at the rate of 1 in 1000 live infants. In this paper, a family carrying one of the rare RobTs was presented and some features of all kinds of RobTs were reviewed.

Case Presentation

A couple with a history of three miscarriages was referred to Omid Health Clinic of Hamadan, Iran. The karyotype of the woman was 45,XX, rob(14;15)(q10;q10) and she exhibited phenotypically good health. Karyotype analysis of proband's uncle and his wife with a consanguineous marriage revealed that they were both carriers of rob(14;15). This couple had six offspring, three of which were dead, and the other three were alive with a normal phenotype. Besides, this couple had an unborn child, with a karyotype of 44,XX,rob(14;15)(q10;q10).

Conclusion

These observations showed that genetic counseling, pedigree, and chromosomal analysis are needed to discover the cause of spontaneous abortion, stillbirth, congenital anomalies, sudden infant death syndrome (SIDS), etc. Moreover, families carrying RobTs would be offered prenatal diagnosis screening tests and, if necessary, assisted reproductive technology methods to assist with preimplantation genetic test for structural rearrangement (PGT-SR) reproduction.