The Role of miRNA Molecules and DNA-Methylation on Expression of Circadian Rhythm Genes in Kids with Mental Disorders

The variation of circadian rhythm genes is involved in mental disorders in kids, and the disrubance of circadian rhythm considered as a risk factor to the development of most mental disorders.Our aim was to study the estimated the role of miRNA molecules( miRNA24, miRNA449a, and miRNA102 on regulated for Per1, Per2, and Per3) and DNA methylation on gene expression of circadian clock genes .The study sample comprised of 40 patient of kids their ages range between (2 -12 years ) having mental disorders , and 20 sample of healthy kids as a control .The study topics were divided into 3 sections: first, determining the level of gene expression for Per1, Per2, and Per3 genes using the qRT-PCR technique.Second section: determination of the level of Non-coding RNA molecules that regulate Per family genes using the qRT-PCR technique.The third section measures the percentage of methylation in the promoter of Per family genes using the PCR technique.The results of the first section showed a significant decrease in the Per1 gene expression; it was the value of folding expression cDNA Per1 gene = 0.33, and a significant increase in the Per2 and Per3 genes; it was the value of folding expression cDNA Per2 gene = 1.76 and folding expression cDNA Per3 gene = 1.58.The results of the second section showed a significant decrease in miRNA gene expression; the value of folding expression cDNA miRNA24 Per1 gene = 0.41, foldin expression cDNA miRNA449a Per2 gene = 0.20, and folding expression cDNA miRNA102 Per3 gene = 0.56.The results of the third section of the DNA methylation showed that DNA methylation in promoter of the Per1 gene was present in 50% of the samples, in the promoter of the Per2 gene, in 43% of the samples, and in the promoter of the Per3 gene, in 0% of the samples.