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Schizophrenia is a prevalent psychiatric disorder with a complex etiology. Mitochondrial dysfunction has been frequently reported in schizophrenia. Phosphatase and tension homologue-induced kinase 1 (PINK1) and presenilin-associated rhomboid-like protease (PARL) are mitochondrial proteins, and genetic variants of these two genes may confer genetic susceptibility to schizophrenia by influencing mitochondrial function. In this study, we conducted a two-stage genetic association study to test this hypothesis. We genotyped 4 PINK1 and 5 PARL genetic variants and evaluated the potential association of the 9 SNPs with schizophrenia in two independent case-control cohorts of 2510 Han Chinese individuals. No positive association of common genetic variants of the PINK1 and PARL genes with schizophrenia was identified in our samples after Bonferroni correction. Re-analysis of the newly updated Psychiatric Genetics Consortium (PGC) data sets confirmed our negative result. Intriguingly, one PINK1 SNP (rs10916832), which showed a marginally significant association in only Hunan samples ( P = 0.032), is associated with the expression of a schizophrenia susceptible gene KIF17 according to the expression quantitative trait locus (eQTL) analysis. Our study indicated that common genetic variants of the PINK1 and PARL genes are unlikely to be involved in schizophrenia. Further studies are essential to characterize the role of the PINK1 and PARL genes in schizophrenia. [ABSTRACT FROM AUTHOR]

Epidemiological studies have indicated that both maternal bacterial and viral infections during pregnancy increase the risk of schizophrenia among offspring, but to date there is not clear explanation for this increased risk. Previously, the decreased C4b-binding protein (C4BP), a potent circulating soluble inhibitor of the classical and lectin pathways of complement, was reported to be associated with risk of schizophrenia. Here, we analyzed 4 common single nucleotide polymorphisms (SNPs) of C4BPB and 5 SNPs of C4BPA in a group of 556 schizophrenia patients and a matched group of 610 healthy controls to see if the genes C4BPB and C4BPA, which encode C4BP, may confer a susceptibility to schizophrenia. Comparing the genotype and allele frequencies of those SNPs between cases and controls, we found no association between the C4BPB / C4BPA variants and schizophrenia. Our results provided preliminary evidence that C4BPB / C4BPA may not confer susceptibility to schizophrenia among Han Chinese. Further genetic studies from large-scale population are required to obtain more conclusive results. [ABSTRACT FROM AUTHOR]

Highlights: [•] A two-stage study aimed at identifying association of LRRK2 with schizophrenia. [•] 12 LRRK2 SNPs were analyzed in Han Chinese with and without schizophrenia. [•] Genotype, allele and haplotype frequencies were compared between cases and controls. [•] None of the 12 analyzed SNPs showed a positive association with schizophrenia. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunction has been widely reported in psychiatric and neurodegenerative diseases. We aimed to investigate the association between matrilineal structures of Han Chinese populations and Alzheimer's disease (AD) by a 2-stage case-control study: A total of 341 AD patients and 435 normal individuals from Southwest China were analyzed for mitochondrial DNA sequence variations and were classified into respective haplogroups. A total of 371 AD patients and 470 normal individuals from East China, as validation samples, were genotyped for the variants defining the risk haplogroup. Haplogroup B5 had a significantly higher frequency in AD patients (7.33%) than in control subjects (3.68%) from Southwest China, and we found a similar pattern of higher frequency of B5 in patients in the case-control sample from East China. In the combined population, association of haplogroup B5 with AD risk was strengthened ( p = 0.02; odds ratio = 1.74; 95% confidence interval = 1.10–2.76). In lymphoblastoid cell lines belonging to haplogroup B5a, we observed significantly increased reactive oxygen species and decreased mitochondrial mass. Hela cells with stable expression of the MT-ATP6 gene with B5-defining variant m.8584G>A also showed a significantly decreased mitochondrial function. Taken together, our results indicated that haplogroup B5 conferred genetic susceptibility to AD in Han Chinese, and this effect was most likely mediated by ancient variant m.8584G>A. The predisposing effect of B5 to AD is consistent with the ancestral-susceptibility model of complex diseases. [ABSTRACT FROM AUTHOR]

Abstract: The leucine-rich repeat kinase–2 (LRRK2) gene has been regarded as 1 of the most common genetic causes of Parkinson's disease (PD). We hypothesized that LRRK2-susceptible allele(s) for PD might pose a risk for Alzheimer's disease (AD). In this study, we screened 12 LRRK2 gene variants in 2 independent cohorts from southwestern China (341 AD patients and 435 normal individuals) and eastern China (297 AD patients and 384 normal individuals), to discern the potential association between this gene and AD. No variant was identified to be associated with AD in either case-control sample. As both of the cohorts were of Han Chinese origin, we combined the LRRK2 variant data for the 2 sample sets together (a total of 638 AD patients and 819 normal individuals) and still found no association between the LRRK2 gene and AD, suggesting that LRRK2 gene variants may not affect the development of AD in Han Chinese individuals. [Copyright &y& Elsevier]