Human leukocyte antigen (HLA) is an invaluable marker for anthropological studies because of its extreme polymorphism. Most of the studies carried out in Chinese populations are about HLA class II genes, but few about class I genes. In the present study, we investigated HLA class I polymorphism using polymerase chain reaction-sequencing-based typing (PCR-SBT) method in 104 unrelated Han individuals in Meizhou of Guangdong, southern China. Twenty-three HLA-A, 43 HLA-B and 27 HLA-C alleles were identified and allele frequencies and two-locus (C/B) and three-locus (A/C/B) haplotypes were statistically analysed. The most frequent HLA-A allele is A*110101 with a frequency of 30.3%, followed by A*24020101 (22.2%) and A*2420 (11.6%). Among the 43 detected HLA-B alleles, B*5801 (17.0%), B*400101 (15.5%) and B*4601 (10.0%) were frequently observed. Among the 27 detected C alleles, the most predominant one is Cw*07020101 (25.8%), followed by Cw*0717 (14.7%). The most frequent HLA-C/B two-locus haplotype is Cw*07020101/B*400101 (10.1%). The most common HLA-A/C/B three-locus haplotype in Meizhou Han is A*110101/Cw*07020101/B*400101 (3.4%). Phylogenetic tree based on HLA class I allele frequencies genetically suggested that Meizhou Han has an affinity to southern Asian populations. The result may also reflect an admixture of Han and ethnic minorities of southern China.
Introduction
Altered DNA methylation in the FK506 binding protein 5 (FKBP5) gene has been shown to regulate stress response, which may serve as a biomarker of depression and a promising candidate for explaining sexual differences. However, there is no consistent conclusion so far.
Objectives
The present study aimed to test the associations of FKBP5 DNA methylation with depressive symptoms and whether these associations were influenced by sex.
Methods
A nested case-control study comprising 87 cases and 151 controls was conducted in South China from January 2019 and December 2019. Peripheral blood for DNA extraction and DNA methylation analysis of FKBP5 gene promoter was collected, and severity of depressive symptoms was assessed at baseline and after one year follow-up.
Results
Compared to healthy controls, lower methylation percentage of FKBP5-12 CpG 1 was observed in adolescents with depressive symptoms after adjusting covariates (case: 0.94 ± 2.00, control: 0.47 ± 0.92; F = 5.41, P = 0.021). In addition, hypomethylation of FKBP5 CpG sites was not an independent risk factor for depressive symptoms after adjustment for environmental stress factors (P > 0.05). No significant sex differences were found in the association of FKBP5 gene methylation with depressive symptoms.
Conclusions
Lower levels of FKBP5 methylation were found in adolescents with depressive symptoms. Our study supported that the epigenetic factors did not act alone in the development of depressive symptoms. Taken together, these findings contribute to a better understanding of complex mechanisms of gene-environment interactions involved in depression.
Disclosure
No significant relationships.
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