Association study of a (TG)n dinucleotide repeat at chromosome 15q13.3 and schizophrenia in the Chinese population.

Linkage studies have suggested that chromosome 15q13-q14 may harbor a susceptibility locus for schizophrenia. In the current study, the association between a (TG)n dinucleotide repeat polymorphism at D15S976 and schizophrenia was investigated using two independent samples from the Han Chinese population. In a population-based study, no significant difference was found between the genotype and allele frequency distributions in schizophrenia patients and control subjects.

[Association study of an (AC)n dinucleotide repeat and schizophrenia in Asian and European populations].

Linkage studies have suggested that chromosome 15q13-q14 may harbor a susceptibility locus for schizophrenia. In the current study, the association between a (AC)n dinucleotide repeat polymorphism at D15S118 and schizophrenia was investigated using three independent samples from the Han Chinese population and the Scotland population. In the population-based study, a significant difference was found between the allele frequency distributions in schizophrenia patients and control subjects in the Scottish samples (P = 0.

Serum prolactin levels, plasma risperidone levels, polymorphism of cytochrome P450 2D6 and clinical response in patients with schizophrenia.

The object of this study is to assess 1) the relationship between plasma antipsychotic drug concentration, serum prolactin levels and the clinical efficacy of risperidone, 2) the relationship between the CYP2D6 polymorphisms and metabolizing of risperidone and 3) the role of 9-hydroxyrisperidone in elevating prolactin levels. One-hundred and eighteen Chinese schizophrenia patients (40 males, 78 females, age 15-60 years) were given risperidone at dosages ranging from 2-8 mg/day for 8 weeks. Clinical efficacy was determined using the Brief Psychiatric Rating Scores (BPRS).

Response of risperidone treatment may be associated with polymorphisms of HTT gene in Chinese schizophrenia patients.

Serotonin transporter (5-HTT) is a key component of the serotonergic neurotransmitter system. Few studies have focused on polymorphisms of the serotonin transporter and antipsychotic response and, in particular, there have so far been no published studies on the association between the serotonin transporter and response to risperidone. This study examined the relationship between two polymorphisms of the serotonin transporter and the efficacy of risperidone treatment in 129 patients with schizophrenia.

The DNA methylation profile within the 5'-regulatory region of DRD2 in discordant sib pairs with schizophrenia.

Studies of discordance in monozygotic twins have demonstrated that environmental effects play an important role in the pathogenesis of schizophrenia. DNA microarray analysis has revealed upregulation of the DRD2 gene in peripheral blood lymphocytes of schizophrenic patients. We hypothesized that this expression alteration could involve the DNA (CpG) methylation status that is implicated to the transcription status of the gene and in this study we used bisulfited sequence analysis to determine the DNA methylation status of a typical CpGs island within the 5'-regulatory region of DRD2 in peripheral blood lymphocytes from 48 discordant sib pairs suffering from schizophrenia.

Association of DRD2 polymorphisms and chlorpromazine-induced extrapyramidal syndrome in Chinese schizophrenic patients.

Aim: Extrapyramidal syndrome (EPS) is most commonly affected by typical antipsychotic drugs that have a high affinity with the D2 receptor. Recently, many research groups have reported on the positive relationship between the genetic variations in the DRD2 gene and the therapeutic response in schizophrenia patients as a result of the role of variations in the receptor in modulating receptor expression. In this study, we evaluate the role DRD2 plays in chlorpromazine-induced EPS in schizophrenic patients.

Population-based and family-based association studies of an (AC)n dinucleotide repeat in alpha-7 nicotinic receptor subunit gene and schizophrenia.

The human alpha-7 neuronal nicotinic receptor subunit (CHRNA7) gene, located at chromosome 15q13.2, represents a strong candidate gene for schizophrenia. We have examined an (AC)n dinucleotide repeat in intron 2 of the CHRNA7 gene, which was previously shown to be strongly linked with schizophrenia, using both population-based and family-based association studies.

Catechol-O-methyltransferase gene Val/Met functional polymorphism and risk of schizophrenia: a large-scale association study plus meta-analysis.

Background: A common functional polymorphism (Val/Met) in the catechol-O-methyltransferase gene (COMT) that markedly affects enzyme activity has been shown to affect executive cognition and the physiology of the prefrontal cortex in humans. It is hypothesized that the high activity Val allele slightly increases risk for schizophrenia through its effect on dopamine-mediated prefrontal information processing.

Methods: We compared the allele/genotype frequencies of the Val/Met polymorphism in a large independent patient-control sample (862 patient and 928 healthy control subjects) from Han Chinese population, and an update meta-analysis was performed to assess the collective evidence across individual studies.

Polymorphism of Prodynorphin promoter is associated with schizophrenia in Chinese population.

Aim: To investigate the correlation between single nucleotide polymorphisms (SNPs) of functional candidate gene Prodynorphin (PDYN) and schizophrenia.

Methods: SNPs in the promoter and exon regions of PDYN were screened and genotyped for association study in a cohort of Chinese Han schizophrenia cases and controls.

Results: Two SNPs PDYN-1576C>T and PDYN-946C>G were identified in the promoter region but PDYN-946C>G showed significant differences of allele distribution (x2=6.

Genetic structure adds power to detect schizophrenia susceptibility at SLIT3 in the Chinese Han population.

The Chinese Han population, the largest population in the world, has traditionally been geographically divided into two parts, the Southern Han and Northern Han. In practice, however, these commonly used ethnic labels are both insufficient and inaccurate as descriptors of inferred genetic clustering, and can lead to the observation of "spurious association" as well as the concealment of real association. In this study, we attempted to address this problem by using 14 microsatellite markers to reconstruct the population genetic structure in 768 Han Chinese samples, including 384 Southern Han and 384 Northern Han, and in samples from Chinese minorities including 48 Yao and 48 BouYei subjects.

[Transmission disequilibrium test of polymorphisms of serotonin transporter gene and schizophrenia based on family trios].

Objective: To investigate the relationship between two polymorphisms (Intronic VNTR and 5-HTTLPR) of the serotonin transporter gene and schizophrenia.

Methods: A set of 314 schizophrenic trio samples collected from Shanghai, Xi'an and Jilin regions of China independently was subjected to analysis of the polymorphisms by transmission/disequilibrium test(TDT).

Results: No significantly preferential transmission of any allele was detected from both polymorphisms investigated.

A family-based association study of T1945C polymorphism in the proline dehydrogenase gene and schizophrenia in the Chinese population.

Previous studies have reported genetic linkage evidence for a candidate gene of schizophrenia on chromosome 22q11 but no genes in this region have been really confirmed to be involved in the etiology of schizophrenia so far. Very recently, the proline dehydrogenase gene (PRODH), located in the most centromeric part of the 22q11 microdeletion region, has been reported to be strongly associated with schizophrenia from three sets of independent samples and the most significant evidence for association was derived from a single nucleotide polymorphism-PRODH*1945(T/C). We genotyped this polymorphism in 166 Chinese family trios with schizophrenia from East China.