Diversity of C-line terminations in Iranian populations

Thirteen Iranian populations of diverse origins have been analyzed for C-line terminations, utilizing bilateral palmar prints of 3,158 individuals. Significant bimanual and male/female differences were frequently found in these populations. Interpopulational variation displayed significant heterogeneity. Distance analysis and constructed dendrograms provided separation between the populations, but the dendrograms are not in agreement with the ethnohistoric records of the populations studied.     

Palmar flexion creases in schizophrenia

Palmar flexion creases have been studied in schizophrenics with a family history of schizophrenia or other psychiatric disorders and without such a background, and compared to a control population. Palmar flexion creases have been analyzed according to the method suggested byBali & Chaube (1971). When compared to controls, differences in the DRBC and TRBC frequencies are significant in the subgroup with no family history, supporting the existence of biological heterogeneity in schizophrenia, and of congenital factors when there is no known genetic background.     

Palmar flexion creases and dermatoglyphics among diabetic patients

Palmar dermatoglyphics and flexion creases of 108 male and 65 female patients diagnosed as having diabetes mellitus have been analysed. The control population consists of 536 males and 234 females from the same population. Palmar flexion creases were analysed according to the method suggested by Bali and Chaube ('71). The flexion creases of diabetic patients and the control population are significantly different. The differences between main line formulae in diabetes and controls are significant among males. The differences between C-line types of patients and controls are significant among both sexes. Axial triradii are significant among female patients and controls. The patterns in the interdigital areas IV and II are significantly lower among male and female patients respectively from their controls.     

Recent advances in genetic research on schizophrenia

Evidence for genetic factors in schizophrenia is reviewed with regard to family, twin and adoption studies, and recent advances in molecular genetic technology are applied to explore possible gene loci susceptible to schizophrenia. Application of neuropsychological and neuroimaging methodologies are also reviewed with an aim to develop criteria for defining phenotypes for genetic studies.Plenary Session, Twelfth Joint Annual Conference of Biomedical Sciences, April 20, 1997, Taipei, Taiwan.     

Types and combinations of axial triradii among the 20 Dhangar castes of Maharashtra,India

Bilateral palmar prints of 3000 males belonging to 20 endogamous Dhangar castes of Maharashtra, India, have been analysed for types and combinations of axial triradii after Cummins and Midlo (1943). Altogether 17 types of axial triradii were found among the Dhangars, but only typest, t′, tt″ occur in appreciable frequencies. The magnitude of intercaste differentiation in respect to axial triradii is considerably low; only 13 caste-pairs (6.84%) out of 190 pairs showed significant difference at the 5% level. Compared to several other palmar elements, like palmar true patterns, main line terminations, palmar flexion creases, the axial triradius has a considerably low level of differentiation among these nomadic, seminomadic and settled Dhangar castes. This suggests that the axial triradii are perhaps more stable compared to many other palmar elements. These results need to be confirmed by data from other populations.     

Advances in endophenotyping schizophrenia

The search for the genetic architecture of schizophrenia has employed multiple, often converging strategies. One such strategy entails the use of tracing the heritability and neurobiology of endophenotypes. Endophenotypes are quantifiable traits not visible to the eye, which are thought to reflect an intermediate place on the path from genes to disorder. Endophenotype abnormalities in domains such as neurophysiology or neurocognition occur in schizophrenia patients as well as their clinically “unaffected” relatives, and reflect polymorphisms in the DNA of schizophrenia spectrum subjects which create vulnerability to developing schizophrenia. By identifying the single nucleotide polymorphisms (SNPs) associated with endophenotypes in schizophrenia, psychiatric neuroscientists can select new strong inference based molecular targets for the treatment of schizophrenia.     

Hereditary multiple exostoses and schizophrenia

I report a case of a patient who suffered schizophrenia and multiple exostoses and argue the possible role of EXT gene and nearly chromosomal loci in further genetic investigations related to schizophrenia.     

Pathway analysis of a genome-wide association study in schizophrenia

Objective

The aim of this study was to identify the candidate single nucleotide polymorphisms (SNPs) and candidate mechanisms that contribute to schizophrenia susceptibility and to generate a SNP to gene to pathway hypothesis using an analytical pathway-based approach.

Methods

We used schizophrenia GWAS data of the genotypes of 660,259 SNPs in 1378 controls and 1351 cases of European descent after quality control filtering. ICSNPathway (Identify candidate Causal SNPs and Pathways) analysis was applied to the schizophrenia GWAS dataset. The first stage involved the pre-selection of candidate SNPs by linkage disequilibrium analysis and the functional SNP annotation of the most significant SNPs found. The second stage involved the annotation of biological mechanisms for the pre-selected candidate SNPs using improved-gene set enrichment analysis.

Results

ICSNPathway analysis identified fifteen candidate SNPs, ten candidate pathways, and nine hypothetical biological mechanisms. The most strongly associated potential pathways were as follows. First, rs1644731 and rs1644730 to RDH8 to estrogen biosynthetic process (p < 0.001, FDR < 0.001). The genes involved in this pathway are RDH8 and HSD3B1 (p < 0.05). All-trans-retinol dehydrogenase (RDH8) is a visual cycle enzyme that reduces all-trans-retinal to all-trans-retinol in the presence of NADPH. The chemical reactions and pathways involved result in the formation of estrogens, which are C18 steroid hormones that can stimulate the development of female sexual characteristics. Second, rs1146031 to ACVR1 to mesoderm formation and activin binding (p < 0.001, FDR = 0.032, 0.034). Two of 15 candidate genes are known genes associated with schizophrenia: KCNQ2 and APOL2. One of the 10 candidate pathways, estrogen biosynthetic process, is known to be associated with schizophrenia (p < 0.001, FDR < 0.001). However, 13 of candidate genes (RDH8, ACVR1, PSMD9, KCNAB1, SLC17A3, ARCN1, COG7, STAB2, LRPAP1, STAB1, CXCL16, COL4A4, EXOSC3) and 9 of candidate pathways were novel.

Conclusion

By applying ICSNPathway analysis to schizophrenia GWAS data, we identified candidate SNPs, genes like KCNQ2 and APOL2 and pathways involving the estrogen biosynthetic process may contribute to schizophrenia susceptibility. Further analyses are needed to validate the results of this analysis.     

微生物在精神分裂症发病机制的研究现状

脑和肠道微生物群之间的相互作用逐渐被揭示。目前已经提出脑-肠轴失调和异常与各种中枢神经系统疾病有关。精神分裂症是一种病因不明的严重精神障碍。最近研究表明,肠道微生物的组成和数量变化会通过肠道菌群-肠-脑轴影响人类的认知和社会行为,这意味着肠道菌群在精神分裂症患者中可能起着重要的作用,并有望成为精神分裂症新的治疗靶点。本文综述了肠道菌群与精神分裂症相关性的研究进展,为预防和治疗精神分裂症等精神障碍类疾病提供了理论依据。     

Impaired associative learning in schizophrenia: behavioral and computational studies

Associative learning is a central building block of human cognition and in large part depends on mechanisms of synaptic plasticity, memory capacity and fronto–hippocampal interactions. A disorder like schizophrenia is thought to be characterized by altered plasticity, and impaired frontal and hippocampal function. Understanding the expression of this dysfunction through appropriate experimental studies, and understanding the processes that may give rise to impaired behavior through biologically plausible computational models will help clarify the nature of these deficits. We present a preliminary computational model designed to capture learning dynamics in healthy control and schizophrenia subjects. Experimental data was collected on a spatial-object paired-associate learning task. The task evinces classic patterns of negatively accelerated learning in both healthy control subjects and patients, with patients demonstrating lower rates of learning than controls. Our rudimentary computational model of the task was based on biologically plausible assumptions, including the separation of dorsal/spatial and ventral/object visual streams, implementation of rules of learning, the explicit parameterization of learning rates (a plausible surrogate for synaptic plasticity), and learning capacity (a plausible surrogate for memory capacity). Reductions in learning dynamics in schizophrenia were well-modeled by reductions in learning rate and learning capacity. The synergy between experimental research and a detailed computational model of performance provides a framework within which to infer plausible biological bases of impaired learning dynamics in schizophrenia.     

Epigenetic mechanisms in schizophrenia

Epidemiological research suggests that both an individual's genes and the environment underlie the pathophysiology of schizophrenia. Molecular mechanisms mediating the interplay between genes and the environment are likely to have a significant role in the onset of the disorder. Recent work indicates that epigenetic mechanisms, or the chemical markings of the DNA and the surrounding histone proteins, remain labile through the lifespan and can be altered by environmental factors. Thus, epigenetic mechanisms are an attractive molecular hypothesis for environmental contributions to schizophrenia. In this review, we first present an overview of schizophrenia and discuss the role of nature versus nurture in its pathology, where ‘nature’ is considered to be inherited or genetic vulnerability to schizophrenia, and ‘nurture’ is proposed to exert its effects through epigenetic mechanisms. Second, we define DNA methylation and discuss the evidence for its role in schizophrenia. Third, we define posttranslational histone modifications and discuss their place in schizophrenia. This research is likely to lead to the development of epigenetic therapy, which holds the promise of alleviating cognitive deficits associated with schizophrenia.     

Molecular links between mitochondrial dysfunctions and schizophrenia

Schizophrenia is a complex neuropsychiatric disorder with both neurochemical and neurodevelopmental components in the pathogenesis. Growing pieces of evidence indicate that schizophrenia has pathological components that can be attributable to the abnormalities of mitochondrial function, which is supported by the recent finding suggesting mitochondrial roles for Disrupted-in-Schizophrenia 1 (DISC1). In this minireview, we briefly summarize the current understanding of the molecular links between mitochondrial dysfunctions and the pathogenesis of schizophrenia, covering recent findings from human genetics, functional genomics, proteomics, and molecular and cell biological approaches.     

Prolactin and schizophrenia: clinical consequences of hyperprolactinaemia

Prolactin is a polypeptide hormone that is synthesized and secreted from specialised cells of the anterior pituitary gland, known as lactotrophs. The hormone was given it's name because extracts from the bovine pituitary gland caused growth of the crop sac and stimulated the elaboration of crop milk in pigeons, and promoted lactation in rabbits. Although prolactin is best known for the multiple effects it exerts on the mammary gland, it has over 300 separate biological activities not represented by its name. It sub serves multiple roles in reproduction other than lactation and is an important modulator of homeostasis in the mammalian organism. Hence Bern and Nicoll suggested renaming it "omnipotin or versatilin". Schizophrenia is a severe psychiatric disorder that affects approximately one percent of the population worldwide. It is well established that traditional typical anti-psychotics elevate prolactin levels. It is also agreed that the serum prolactin concentration is not elevated in patients with schizophrenia who are not receiving anti-psychotic medication. Hyperprolactinaemia has direct effects on the brain and on other organs. Direct consequences include galactorrhoea. Indirect consequences of hyperprolactinaemia include oligomenorrhoea and amenorrhoea, erratic or absent ovulation, sexual dysfunction, reduced bone mineral density and cardiovascular disease. With the advent of prolactin sparing anti-psychotics, ample consideration needs to be given to the physiological consequences of hyperprolactinaemia in schizophrenic patients. In this paper we will examine molecular biology, secretion and physiology of prolactin. The consequences of hyperprolactinaemia in humans including effects on fertility, sexual dysfunction, bone mineral density, cardiovascular disease, changes in psychopathology and movement disorders will be reviewed. The literature on the association between schizophrenia, anti-psychotic medication and hyperprolactinaemia and more specifically on the consequences of this hyperprolactinaemia in schizophrenic patients will also be reviewed.     

Association of G72/G30 with schizophrenia in the Chinese population

Recently, the G72 gene was reported to be associated with schizophrenia in the French Canadian and Russian populations. Here, we report the results obtained from the study of six single-nucleotide polymorphisms (SNPs: rs3916965, rs3916967, rs2391191, rs1935062, rs778293, and rs3918342), which span an 82-kb region covering the complementary DNA sequences of G72 and G30, in 537 schizophrenia cases and 538 controls of the Han Chinese. In this work, we have identified statistically significant differences in allele distributions of two markers rs3916965 (P = 0.019) and rs2391191 (P = 0.0010), and a highly significant association between haplotype AGAC of the G72/G30 locus (P = 1.7 x 10(-4)) and schizophrenia. Our data provide further evidence that markers of the G72/G30 genes are associated with schizophrenia in a non-Caucasian population.     

肠道菌群与精神分裂症的研究进展

精神分裂症是一种精神障碍疾病。除了遗传因素外,一些环境因素也参与了精神分裂症的发生,肠道微生物群是近年来发现的主要影响因素之一。研究表明,精神分裂症患者肠道菌群普遍发生了紊乱,肠道菌群通过肠-脑轴影响神经功能和疾病。肠道菌群可以通过影响神经系统发育、免疫和代谢功能来诱导精神分裂症的发生,肠道菌群可能是精神分裂症防治的有效靶点,调节肠道菌群可能是防治精神分裂症的一种潜在方法。本文就精神分裂症的易感因素、肠道菌群在精神分裂症中的作用、机制以及防治策略等方面的研究进展进行综述。     

The relationship between membrane pathology and language disorder in schizophrenia

Receptive language disorder in schizophrenia has been hypothesized to involve a fundamental deficit in the temporal (time-based) dynamics of brain function that includes disruptions to patterns of activation and synchronization. In this paper, candidate mechanisms and pathways that could account for this basic deficit are discussed. Parallels are identified between the patterns of language dysfunction observed for schizophrenia and dyslexia, two separate clinical disorders that may share a common abnormality in cell membrane phospholipids. A heuristic is proposed which details a trajectory involving an interaction of brain fatty acids and second-messenger function that modulates synaptic efficacy, and, in turn, influences language processing in schizophrenia patients. It is additionally hypothesized that a primary deficit of functional excitation originating in the cerebellum, in combination with a compensatory decrease of functional inhibition in the prefrontal cortex, influences receptive language dysfunction in schizophrenia.     

RELN基因启动子区SNP位点与精神分裂症的相关性分析

目前有很多证据证明RELN基因在世界人群中是一个精神分裂症的致病基因.基于之前报道过的RELN基因在精神分裂症患者中表达下降的事实,可以推测在RELN基因启动子区可能包含影响精神分裂症发生的多态位点.该研究分析了中国西南地区病例——对照人群中(940位患者和1369位正常人)RELN基因启动子区的3个单核苷酸多态性位点与精神分裂症的相关性.研究结果显示,这些多态位点都不与精神分裂症相关,表明RELN基因的致病位点并不在其启动子区.将前人研究结果与该研究结果进行综合分析(共2843个样本),结果仍不显著.因此,该研究表明,RELN基因启动子区的单核苷酸多态性位点在中国人群中并不与精神分裂症相关.