Comparison of two groups for the apolipoprotein E polymorphisms by using next generation sequencing: The first group with three consecutive abortions and the second group with at most one abortion in three consecutive pregnancies

Abstract

The importance of apolipoprotein E genotypes and allelic polymorphisms in the etiology of recurrent miscarriage is controversial. We plan to investigate this in a two-group study involving more than a thousand participants. In total, 1046 subjects (802 participants in the first group, 244 participants in the second group) were investigated. Women in the first group had a history of ≥3 consecutive spontaneous miscarriage and women in the second group had at most one miscarriage in three consecutive pregnancies. The participants with the following evidence and symptoms were excluded from both groups; structural uterine abnormality, chrosomal abnormalities and polymorphisms, hormonal imbalance, anti-nuclear antibodies, anti-phospholipid antibodies, lupus anticoagulant and homozygous genotype for FV-Leiden, MTHFR C677T, MTHFR A1298C, prothrombin 20210G>A and plasminogen activator inhibitor 4G/5G polymorphisms. We found similar apolipoprotein E allelic frequencies and genotype distributions in both groups. The frequencies of ε2 alleles were 4.1% in the first group and 2.9% in the second group, whereas those of ε3 alleles were 90.8% and 93% in the first group and the second group, respectively and ε4 alleles were 5.1% in the first group and 4.1% in the second group. The genotypes of Apo E observed in the first and the second group respectively were as follows; ε2/ε3 (7.5% and 5.7%), ε3/ε3 (82.7% and 86.5%), ε3/ε4 (8.7% and 7.4%), ε4/ε4 (0.5% and 0.4%) and ε2/ε4 (0.6% and 0). Our data did not support a possible association between apolipoprotein E genotypes and allelic frequencies, and recurrent miscarriages. We believe that the studies excluding the etiological factors that were previously found to be related with any condition are more valuable in the scope of showing the cause–effect relationship.