Health Sciences and Technologies Program, University of Brasilia, Faculty of Ceilândia, Brasilia, DF, Brazil.
University of Brasilia, Faculty of Ceilândia, Brasilia, DF, Brazil.
Behav Neurol. 2021 Nov 1;2021:7117613. doi: 10.1155/2021/7117613. eCollection 2021.
Major depressive disorder (MDD) still has an unknown etiology and mechanisms. Many studies have been conducted seeking to associate and understand the connection of different genetic variants to this disease. Researchers have extensively studied the brain-derived neurotrophic factor (BDNF) Val66Met genetic variant in MDD; yet, their findings remain inconsistent. This systematic review sought to verify the GG (Val/Val) genotype frequency fluctuation in different populations with MDD. For this, we searched in different databases and, after applying the eligibility criteria, selected 17 articles. Most studies demonstrate the higher frequency of the ancestral (wild) GG (Val/Val) genotype, although associations of the polymorphic A (Met) allele, changes in BDNF protein serum levels, or both were also found in MDD, whether related to the disease's development or other factors. Nevertheless, despite these findings, disagreements between several studies are seen. For this reason, further BDNF Val66Met genetic variant studies should not only bridge the gap in the knowledge of this polymorphism's role in MDD's different facets but also analyze the genotypic and phenotypic heterogeneity in different populations to help provide a better quality of life for patients.
重度抑郁症（MDD）的病因和发病机制仍不清楚。许多研究都试图将不同的遗传变异与这种疾病联系起来，并理解其关联。研究人员已经广泛研究了脑源性神经营养因子（BDNF）Val66Met 基因变异与 MDD 的关系；然而，他们的发现仍然不一致。本系统评价旨在验证不同 MDD 人群中 GG（Val/Val）基因型频率的波动。为此，我们在不同的数据库中进行了搜索，并在应用入选标准后，选择了 17 篇文章。大多数研究表明，原始（野生）GG（Val/Val）基因型的频率较高，尽管在 MDD 中也发现了多态性 A（Met）等位基因的关联、BDNF 蛋白血清水平的变化或两者兼而有之，无论是与疾病的发展还是其他因素有关。然而，尽管有这些发现，但几个研究之间存在分歧。因此，进一步的 BDNF Val66Met 基因变异研究不仅应该弥合该多态性在 MDD 不同方面作用的知识差距，还应该分析不同人群中的基因型和表型异质性，以帮助为患者提供更好的生活质量。
