No association between estrogen receptor gene polymorphisms and premature thelarche in girls

Abstract

Objective: Premature thelarche (PT) is a benign, nonprogressive condition defined as isolated breast development. While the pathophysiology of PT remains unclear, increased sensitivity to estrogen may cause PT. The aim of this study was to investigate the association between polymorphisms in the estrogen receptor alpha (ERα) gene and PT in girls.

Methods: In this case–control study, we examined 96 girls referred for early breast development (before the age of 8 years). The control group included healthy Korean females with normal pubertal progression. Anthropometric and hormonal parameters were measured and PvuII and XbaI ERα gene polymorphisms were evaluated by PCR. Out of the 96 girls, all coding exon and exon-intron boundaries of ERα were sequenced from the DNA of 46 girls.

Results: There was no significant difference in the distribution of PvuII and XbaI polymorphisms between patients and controls. However, the carriers of XbaI polymorphisms had more advanced Tanner stage than did the non-carriers. Also, four ERα gene polymorphisms were previously identified, but these polymorphisms had no clinical significance.

Conclusion: No association was found between the ERα gene polymorphisms and PT in girls. However, XbaI polymorphisms may contribute to early breast budding.

Chinese abstract

目的：乳房过早发育（PT）是一种良性的、非进展性的单纯乳房发育状态。虽然PT的病理生理学仍不明确, 但雌激素敏感性的增加可能导致PT。本研究的目的是观察雌激素受体α（ERα）基因多态性与幼女PT的关系。

方法：在本病例对照研究中, 我们纳入了96名8岁之前乳房发育的幼女。对照组包括正常青春期发育的健康韩国女性。手段包括体格检查、激素测定以及 PCR评估PvuII和XbaI ERα基因多态性, 并对其中46名幼女DNA 的ERα基因所编码的外显子和外显子-内含子边界进行测序。

结果：实验组和对照组之间PvuII和XbaI基因多态性分布无显著差异。然而, XbaI多态性的载体具有比非载体更高级的Tanner阶段。此外, 之前鉴定出的4种ERα基因多态性是没有临床意义的。

结论：幼女ERα基因多态性与PT无相关性。然而, XbaI多态性可能有助于早期乳腺萌芽。

Keywords:

• Breast development
• estrogen receptor alpha
• premature thelarche

Acknowledgements

This study was supported by a grant from the Abbott fund. The biospecimens and data used for this study were provided by the Biobank of Ajou University Hospital, a member of Korea Biobank Network.

Declaration of interest

None of the authors has any conflict of interest to disclose. We confirm that we have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.