Major Depressive Disorder (MDD) is a disabling and particularly persistent mental disorder that is considered to be a priority public health problem. The active human dopamine transporter (DAT), which is encoded by the SLC6A3 gene, regulates the dopamine concentration in the synaptic cleft. In this sense, this neurotransmitter is primordial in modulating human emotions. This systematic review aims to verify the SLC6A3 (DAT1) 3′UTR VNTR (rs28363170) gene variant’s SS (9R/9R) genotype and S (9R) allele frequency fluctuation and its influence on the modulation of pharmacotherapy in MDD. For this purpose, we searched different databases, and after applying the eligibility criteria, six articles were selected. Studies have shown an association between the SS (9R/9R) genotypic and S (9R) allelic presence with the risk of developing MDD, in addition to influencing the decrease in response to antidepressant therapy. However, despite the findings, disagreements were observed between other studies. For this reason, further studies with the SLC6A3 3′UTR VNTR (rs28363170) variant in different populations are necessary to understand this polymorphism’s role in the onset of this disease.

Major depressive disorder (MDD) affects over 300 million people globally and has a multifactorial etiology. The CYP2C19 enzyme, involved in metabolizing certain antidepressants, can influence treatment response. Following the PRISMA protocol and PECOS strategy, this systematic review assessed the variation in common CYP2C19 gene variants’ frequencies across populations with MDD, evaluating their impact on clinical characteristics and treatment response. We comprehensively searched five databases, identifying 240 articles, of which only nine within the last decade met our inclusion criteria. Except for one study that achieved 74.28% of STROPS items, the rest met at least 75% of GRIPS and STROPS guidelines for quality and bias risk assessment. The CYP2C19’s *1 allele, the *1/*1 genotype, and the NM phenotype, considered as references, were generally more frequent. Other CYP2C19 polymorphism frequencies exhibit significant variability across different populations. Some studies associated variants with MDD development, a more extended history of depression, prolonged depressive episodes, and symptom severity, while others reported no such association. Some studies confirmed variants’ effects on escitalopram and citalopram metabolism but not that of other drugs, such as sertraline, venlafaxine, and bupropion. Treatment tolerability and symptom improvement also varied between studies. Despite some common findings, inconsistencies highlight the need for further research to clarify the role of these polymorphisms in MDD and optimize treatment strategies.

Background: Major depressive disorder (MDD) is a disease that has been increasingly affecting more people worldwide. The dopamine D2 receptor (DRD2), encoded by the DRD2 gene, plays critical roles in the brain, one of which is related to reward processes. Aims: The following systematic review aims to analyze the DRD2/ANKK1 TaqIA (rs1800497) polymorphism’s A1 genotype frequency fluctuation in MDD patients and determine its influence on MDD. Methods: Four databases were searched, and the consequent articles were analyzed following the inclusion criteria per the PECOS strategy, resulting in five selected articles. Results: Interestingly, although two articles showed that the A1 allele presence significantly increases the risk of MDD manifestation, most articles did not find a significant association between this DRD2 gene variant and MDD. Conclusions: Most of the included studies were dated, indicating the need for more studies to address the results’ non-conformity with different populations.

Major Depressive Disorder (MDD) has a multifactorial etiology and pathogenesis that significantly impacts an individual’s quality of life. One of the possible correlations for its onset is the activation of inflammatory responses resulting in neurodegeneration and, consequently, the emergence of depressive symptoms. Interleukin-1β is a regulatory cytokine of the immune and nervous systems that acts on several processes, including mood regulation. This systematic review analyzed the IL1B (C-511T) (rs16944) variant’s CC and CT genotype frequencies and their associations with MDD in different populations while also verifying the TT genotype’s influence on response to antidepressant therapy. This review involved searching five databases, and articles were selected according to the PECOS inclusion criteria, resulting in eight articles. The findings highlight distinct clinical outcomes: the CC genotype was more frequently associated with greater MDD symptom severity, whereas the TT genotype was predominantly associated with antidepressant treatment response; thus, these associations should not be considered equivalent in terms of susceptibility to disease onset. However, despite these findings, other studies have found no significant association between this genetic variant and MDD. Therefore, further studies across different populations are needed to better understand the role of this polymorphism in the etiology of this disorder.

Objetivo: Descrever a presença do polimorfismo da região codante do gene CHGA Glu264Asp e associa-lo com as características clinicas da doença. Método: Trata-se de um estudo transversal, descritivo e de caso controle para investigar o polimorfismo da CHGA Glu264Asp por meio de amostras de sangue de 53 indivíduos sendo o grupo caso, formado por 23 pacientes, de ambos os sexos, que sofreram a tireoidectomia e foram submetidos ao tratamento com o Radiofármaco Iodeto de Sódio (I131). Para a genotipagem foi utilizada a técnica PCR-RFLP. Foi adotado o nível de significância de 5%. Resultados: Houve diferença estatística significativa na distribuição alélica entre indivíduos com câncer papilífero da tireoide e os sadios. Com tudo, a presença do alelo G é um fator de risco para o câncer papilífero da tireoide. Observou-se uma correlação entre o genótipo GG com o aumento do nível de TSH em pacientes que apresentavam essa patologia. Conclusão: Demostrou-se que o alelo selvagem pode ser um fator de risco para o desenvolvimento da neoplasia tireoidiana do tipo papilar. Por ser uma doença de etiologia multifatorial, são necessários outros estudos em populações diferentes para melhor compreensão da doença.

Introduction: PCSK9 encodes a protein that regulates cholesterol homeostasis by promoting degradation of the low-density lipoprotein receptor (LDLR), thereby increasing plasma LDL-cholesterol levels and influencing cardiovascular risk