Recurrent miscarriage is associated with the dopamine receptor (DRD2) genotype

Abstract

The purpose of this research is to compare the prevalence of dopamine receptor D2 polymorphisms in women with recurrent miscarriage (RM) and healthy patients. Fifty-four women were enrolled in this case–control study. We performed DNA extraction of peripheral blood, followed by polymerase chain reaction to confirm single-strand polymorphisms and to sequence two polymorphisms: polymorphism 1 (rs6275) and polymorphism 2 (rs6277) in exon 7 of the dopamine receptor D2 (DRD2). The frequency of DRD2 polymorphism 2 (rs6277) was increased in the subjects with RM. An analysis of the DRD2 genotypes demonstrated an odds ratio of 2.37 (1.05–5.36, 95% confidence interval) for the polymorphism 2 (rs6277) in RM. The mean of the serum prolactin level was higher in the patients with RM (12.5 ng/ml) than in healthy women (8.1 ng/ml) p = 0.03. An excess homozygosity of the DRD2 polymorphism suggests a genetic predisposition to RMs, which could result in a mild serum prolactin increase. Thus, because of the potential role of prolactin in reproductive regulation, this polymorphism could play an important role in early pregnancy implantation and pregnancy maintenance.

Chinese abstract

本研究的目的是比较复发性流产患者与健康女性多巴胺受体D2基因多态性的患病率。54名受试者参加了这项病例对照研究。我们从外周血提取DNA，然后通过聚合酶链反应证实单链多态性与序列多态性：多巴胺受体D2（DRD2）的外显子7中的多态性1（rs6275）和多态性2（rs6277）。DRD2多态性2（rs6277）的频率在复发性流产患者中增加。DRD2基因型的分析表明，多态性2（rs6277）在复发性流产患者中优势比为2.37（95%置信区间：1.05–5.36）。复发性流产患者(12.5 ng/ml)的血清泌乳素水平明显高于健康女性(8.1 ng/ml)（P = 0.03）。DRD2基因多态性的过量纯合子表明：复发性流产患者的遗传易感性能够导致血清泌乳素轻度升高。因此，由于泌乳素在生殖调控中的潜在作用，该多态性可能在早期妊娠着床和妊娠维持中发挥重要作用。

• Abortion
• dopamine receptor D2
• polymorphism
• prolactin
• recurrent miscarriage

Declaration of interest

The authors report no declarations of interest.

We are grateful for the financial support provided by Fundo de Incentivo à Pesquisa (FIPE), Hospital de Clínicas de Porto Alegre, Brazil.