Prevalence of Chromosome Inversion Percentric and Paracentric in Recurrent Abortions in Patients Referred to Sarem Women’s Hospital and Fertility Infertility Research Center

Background & Aims: Recurrent abortion affects almost 15% of diagnosed pregnancies. The aim of this study is to present the role of chromosomal inversions in recurrent miscarriages in patients referred to the Cytogenetic laboratory of Sarem fertility and infertility research center and Hospital in Tehran. Chromosome inversions visible under the light microscope are a common class of human balanced structural rearrangements. The material between the two breakpoints reverses orientation, reinserts, and the breaks rejoin. One group of inversions is per centric inversion of chromosome 9, which is usually regarded as a normal population variant.

Materials & Methods: We studied 2299 patients with recurrent abortions referred to Sarem fertility and infertility research center and Hospital during 1996until 2014 for chromosome investigation. The samples were studied using high resolution GTG banding technique. For each patient, a minimum of 15 metaphases was examined by light microscopy.

Results: In total 49 patients showed inversions. Per centric inversion around centromere of chromosome 9 was observed in 29 patients (1.26%) and percentric inversion in heterochromatin region was found in chromosome 1 in one patient and chromosome Y in another patient, and one patient had percentric inversion of chromosome 2. Chromosomal inversion involving other autosomal chromosomes included pericentric inversion of chromosomes 1, 5, 8, 11 and 12, and paracentric inversion of chromosomes 3, 6, 7, 8, and 12 (0.44%).

Conclusion: The chromosomal imbalance of gametes arisen during gametogenesis may produce spontaneous abortions and malformed offspring. This suggests that such inversions should not be ignored and they can play an important role in reproduction failure. However, we have shown that the rate of pericentric inversion of chromosome 9 is similar to normal population (1-2%) and thus of no clinical significance.

Keywords: Chromosome Inversion, Recurrent Abortions, inv (9)