Chromosomal distribution of schizophrenia susceptibility loci

Enrichment analysis of systemic lupus erythematosus susceptible loci identified by genome-wide association studies

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease. Genome-wide association studies (GWAS) have identified several loci associated with susceptibility to the disease. For the current analysis, enrichment analysis was performed using predicted SLE loci. SLE-associated loci were retrieved from the GWAS database. Gene ontology functional annotation and Reactome pathway analysis were performed using the Enrichr online server. A total of 293 loci encoding susceptible SLE proteins were identified. The analysis revealed that genes associated with SLE were primarily involved in cytokine signaling in the immune system, as demonstrated by the Reactome pathway analysis. In addition, gene ontology analysis suggested that SLE-associated genes were primarily involved in the immune system and its functions. Statistical analysis revealed that 9 segments of the human chromosome had a significantly higher number of SLE-associated genes. Specifically, the 6p21.31-p22.2 and 19p13.2-p13.3 contained 34 and 12 SLE-associated genes, respectively. This study showed that rheumatoid arthritis and multiple sclerosis share 33 and 42 genes, respectively, with SLE, and among the shared genes, four genes CD40, STAT4, TYK2, and IL2RA are involved in the cytokine signaling pathway in the immune system. It might suggest that positive regulation of cytokine production pathway is a common pathway among autoimmune diseases.

Association between 15 insertion/deletion genetic polymorphisms and risk of schizophrenia using pooled samples

Schizophrenia is a psychiatric syndrome that affects approximately 1 % of the world population and is among the top 10 reasons for disability. In this case-control study, we investigated the association between 15 insertion/deletion (Indel) polymorphisms and schizophrenia risk using pooled samples. In the present case-control study, 361 individuals with schizophrenia and 360 healthy individuals were included in the study. We examined the insertion/deletion polymorphisms in APOB, ADRA2B, PDCD6IP, LRPAP1, TLR2, DHFR, VEGF, HLA-G, TPA, DBH, UCP2, FADS2, MDM2, TP53 and SLC6A4 genes. Our results revealed that the Del allele of the HLA-G 14bp Indel polymorphism increased the risk of schizophrenia (OR=1.23, 95 % CI=1.01-1.52, p=0.045) and the Alu^- allele of the TPA Alu⁺/Alu^- polymorphism negatively associated with the schizophrenia risk (OR=0.67, 95 % CI=0.54-0.82, p<0.001).

Non-randomness distribution of micro-RNAs on human chromosomes

Background

Micro-RNA (miRNA) is one of the non-coding RNAs that exist in human genome. miRNAs play an important role in the expression of target genes. Several studies have indicated that organization of human genome is not random. In order to investigate the distribution of miRNAs on human chromosomes, the present study was carried out.

Results

Using the data from miRBase database, we found 1913 loci coding for miRNAs (MIRs). Human chromosome bands 1p36, 1q22, 1q24, 2q13, 2q35, 3p21, 6p21, 7q22, 8p23, 8q24, 9q22, 9q34, 11q12-q13, 12q13, 14q32, 16p13, 16q24, 17p13, 17q11, 17q21, 17q25, 19p13, 19q13, 20q13, 21p11, 22q13, and Xq26-q28 were significantly bearing higher number of MIRs. The 14q32 and 19q13 with 4.11 and 3.59 MIRs per mega-base pair, respectively, were the most MIR-richest human chromosomal bands. The number of MIRs on chromosomal bands significantly decreased as a function of distance from telomere (r = − 0.949, df = 5, P = 0.001).

Conclusions

Our current data suggest that MIRs are not randomly distributed on human genomes.