<Emphasis Type="Italic">PTEN</Emphasis> methylation and expression in glioblastomas

The tumor suppressor gene PTEN on chromosome 10q23.3 regulates the Akt signaling pathway and modulates cell growth and apoptosis. The PTEN gene is mutated in 20–40% of glioblastomas. In this study, we assessed whether loss of PTEN expression is also caused epigenetically. Methylation-specific PCR revealed that CpG islands of the PTEN promoter were methylated in 27 of 77 (35%) glioblastomas and in 4 of 11 (36%) glioblastoma cell lines. Only two glioblastomas showed loss of PTEN immunoreactivity in the entire biopsy; both had a missense PTEN mutation and LOH at the PTEN locus, but lacked PTEN methylation. In biopsy specimens with focal loss of PTEN expression, DNA samples extracted from microdissected foci showed PTEN methylation only in areas with loss of PTEN expression. These results suggest that PTEN methylation occurs frequently in glioblastomas and may be associated with focal loss of PTEN expression. However, the correlation between PTEN methylation, PTEN mutations, LOH at the PTEN locus, and loss of PTEN protein expression was inconsistent. Possible reasons for discrepancies between gene status and protein expression include differences in the biological effect of specific PTEN mutations and the possibility that the processed PTEN pseudogene on 9p21 is expressed in glioblastomas and co-reacts with the PTEN antibody.     

<Emphasis Type="Italic">PIK3CA</Emphasis> alterations in primary (de novo) and secondary glioblastomas

We assessed alterations in the EGFR/PTEN/PI3K pathway in 107 primary (de novo) glioblastomas and 32 secondary glioblastomas that progressed from low-grade or anaplastic astrocytomas. SSCP followed by DNA sequencing in exons 9 and 20 of the PIK3CA gene revealed missense mutations in 5/107 (5%) primary and 1/32 (3%) secondary glioblastomas. Quantitative real-time PCR showed PIK3CA amplification (>3 copy numbers) in 14/107 (13%) primary and 3/32 (9%) secondary glioblastomas. Only one glioblastoma showed both PIK3CA mutation and amplification. Taken together with previously published data on EGFR amplification and PTEN mutations, at least one alteration in the EGFR, PTEN, or PIK3CA genes was detected in 63% of primary glioblastomas, which was significantly more frequent than in secondary glioblastomas (31%; P < 0.001). Furthermore, this signaling pathway was altered by either PTEN mutations or PIK3CA amplification in 10 of 12 (83%) malignant glioma cell lines analyzed. These results suggest that the EGFR/PTEN/PI3K pathway is frequently altered in glioblastomas and is a promising target for therapy, in particular for primary glioblastomas.     

Genetic Polymorphism of Glutathione <Emphasis Type="Italic">S</Emphasis>-transferase T1 (<Emphasis Type="Italic">GSTT1</Emphasis>) and QT-Interval in Schizophrenia Patients

Several antipsychotic agents are known to prolong the QT interval in a dose-dependent manner. The antipsychotic drugs are substrates of the phase I of biotransformation enzymes of cytochrome P450. In order to find the possible influence of polymorphism of GSTT1 (a member of class theta glutathione S-transferase) on rate-corrected QT interval (QTc) of schizophrenia patients, the present study was done. Forty-three schizophrenia in-patients participated in the study. The patients were diagnosed as chronic schizophrenia according to structured clinical interview using SCID-I (clinician version) to confirm and document DSM-IV diagnosis. Measurements of QT and RR intervals were recorded using a magnifying grid on lead II. The QTc was calculated according to Bazett’s formula. Polymerase chain reaction-based method was used in order to determine the GSTT1 genotypes. Based on the fitted model of multiple linear regression analysis, QTc decreased in persons with positive GSTT1 genotype in comparison with the null genotype (β = −0.328, t = −2.346, p = 0.024). Active genotype of GSTT1 decreased the QTc. Also, QTc was significantly associated with smoking status; it was decreased in smokers compared with nonsmokers (β = −0.372, t = −2.372, p = 0.014).     

Sequence analysis of <Emphasis Type="Italic">Drd2</Emphasis>, <Emphasis Type="Italic">Drd4</Emphasis>, and <Emphasis Type="Italic">Dat1</Emphasis> in SHR and WKY rat strains

Background  

The Spontaneously Hypertensive Rat (SHR) shows a number of behaviours that closely parallel those seen in children with attention-deficit hyperactivity disorder. These include motor hyperactivity, excessive responses under a fixed-interval/extinction schedule, difficulty in acquiring operant tasks and increased sensitivity to immediate behavioural reinforcement. As in children with ADHD, the behavioural and cognitive deficits in the SHR are responsive to stimulants, including d-amphetamine and d,l-methylphenidate. The non-hyperactive Wistar Kyoto (WKY) rat strain is often used as a control in behavioural studies of the SHR, and WKY itself has been suggested to be a useful animal model of depression. Numerous studies have shown that dopaminergic neurotransmission is altered between the two strains. Human genetic studies have found associations between several dopaminergic genes and both ADHD and depression.     

Genetic association analysis of tagging SNPs in alpha4 and beta2 subunits of neuronal nicotinic acetylcholine receptor genes (<Emphasis Type="Italic">CHRNA4</Emphasis> and <Emphasis Type="Italic">CHRNB2</Emphasis>) with schizophrenia in the Japanese population

Several lines of evidence suggest that nicotinic cholinergic dysfunction may contribute to the cognitive impairments in schizophrenia. The majority of high affinity nicotine binding sites in the human brain have been implicated in heteropentameric alpha4 and beta2 subunits of neuronal nicotinic acetylcholine receptors; therefore, these two neuronal nicotinic acetylcholine receptors genes (CHRNA4 and CHRNB2) are considered to be attractive candidate genes for the pathophysiology of schizophrenia. To represent these two genes in a gene-wide manner, we first evaluated the linkage disequilibrium structure using our own control samples. Thirteen SNPs (7 SNPs for CHRNA4 and 5 SNPs for CHRNB2) were selected as tagging SNPs. Using these tagging SNPs, we then conducted genetic association analysis of case-control samples (738 schizophrenia and 753 controls) in the Japanese population. No significant association was detected in the allele/genotype-wise or haplotype-wise analysis. Our results suggest that CHRNA4 and CHRNB2 do not play a major role in Japanese schizophrenia.     

Community-acquired <Emphasis Type="Italic">Pseudomonas</Emphasis> meningitis causes acute obstructive hydrocephalus

Introduction   Pseudomonas aeruginosa (PS) infection is serious in children and can cause malignant external otitis, endophthalmitis, endocarditis, meningitis, pneumonia, and septicemia (Huang et al. Pediatr Infect Dis J 1). The treatment of Pseudomonas infection requires prompt medical evaluation and appropriate antibiotic treatment. Case report  We report the case of a 6-month-old boy with an unusual presentation of acute obstructive hydrocephalus owing to Pseudomonas meningitis. Treatment with optimal antibiotic begun immediately after the pathogen was recognized and continued for 4 weeks. The patient received prompt surgical intervention for the complication of acute obstructive hydrocephalus. Conclusion  The early stage of obstructive hydrocephalus caused by community-acquired Pseudomonas is rare and should be immediately detected.     

Haploinsufficiency of the <Emphasis Type="Italic">SERPINA6</Emphasis> gene is associated with severe muscle fatigue: A <Emphasis Type="Italic">de novo</Emphasis> mutation in corticosteroid-binding globulin deficiency

Summary. Corticosteroid-binding globulin (SERPINA6) deficiency is an extremely rare hereditary disorder characterized by reduced corticosteroid-binding capacity with normal or low plasma corticosteroid-binding globulin concentration, and normal or low basal cortisol levels associated with hypo-/hypertension and muscle fatigue. Here, we present a patient with severe muscle fatigue, normal blood pressure, and abnormal high saliva cortisol levels following a standardized stress test. This patient was found heterozygous for a de novo 367 asparagine-encoding variant of the corticosteroid-binding globulin gene, previously described as “transcortin Lyon”. Both parents were homozygous for the (“wildtype”) 367 aspartate-encoding allele. To the best of our knowledge, this case represents the first de novo mutation reported for corticosteroid-binding globulin deficiency, implicating a pathogenic role of variants of SERPINA6 in some cases of muscle fatigue.     

Utility of MLPA in deletion analysis of <Emphasis Type="Italic">GCH1</Emphasis> in dopa-responsive dystonia

We applied multiple ligation-dependent probe amplification (MLPA) to patients from three families with characteristic dopa-responsive dystonia (DRD) but no base change in the gene GCH1. We found a complete deletion of GCH1 in affected members of family 1, and partial deletions in affected individuals of family 2 (exons 4-6) and of family 3 (exons 2-6). The findings were confirmed by quantitative real-time PCR. Our investigations demonstrate the utility of MLPA for routine deletion analysis of GCH1 in DRD patients with no sequence changes in this gene.     

Novel <Emphasis Type="Italic">CLCN1</Emphasis> mutations in Taiwanese patients with myotonia congenita

Abstract. We have performed genetic screening on the skeletal muscle chloride channel gene (CLCN1) in Taiwanese population. A total of four patients with myotonia congenita (MC) together with 106 normal individuals were examined. All 23 exons of the CLCN1 gene were analysed by direct sequencing of PCR products to detect the nucleotide changes. Five mutations and three polymorphisms were identified in this study. Among these, three missense mutations (S471F, P575S, D644G) and one polymorphism (T736I) are novel and could be unique to the Taiwanese. In addition, a previously documented recessive G482R mutation was identified in a heterozygous patient and his nonsymptomatic father, indicating that this mutation might indeed function recessively or dominantly with incomplete penetrance. In conclusion, this is the first report of MC in Taiwan with proven CLCN1 gene mutations and showing high molecular heterogeneity in Taiwanese MC patients.     

Association of <Emphasis Type="Italic">CILP</Emphasis>, <Emphasis Type="Italic">COL9A2</Emphasis> and <Emphasis Type="Italic">MMP3</Emphasis> Gene Polymorphisms with Lumbar Disc Degeneration in an Indian Population

Lumbar disc degeneration (LDD) is a multifactorial disorder caused by genetic and environmental factors. Polymorphisms in several structural and inflammatory genes like collagens, aggrecan, matrix metalloproteinases are associated with the risk of disc degeneration. In this study, we analyzed the role of a few important single nucleotide polymorphisms in cartilage intermediate layer protein (CILP), collagen 9A2 (COL9A2) and matrix metalloproteinase 3 (MMP3) genes in LDD from an Indian population. Two hundred patients with LDD and 200 healthy controls were recruited for the study. Genotyping was performed by allelic discrimination assay. The rs2073711 polymorphism (CILP gene - GG genotype) was associated with reduced risk of LDD in the Indian population (OR?=?0.43, p?=?0.016). The rs591058 polymorphism (MMP3 gene - TT genotype) is found to be associated with lower risk among women (OR?=?0.34, p?=?0.041). No significant association was found between COL9A2 polymorphism rs7533552 and the risk of LDD. We conclude that the CILP gene polymorphism (rs2073711) is associated with a lower risk of LDD, the MMP3 (rs591058) gene polymorphism is associated with LDD among women, and the TT genotype confers a lower risk of LDD.     

An association analysis of synapse-associated protein 97 (<Emphasis Type="Italic">SAP97</Emphasis>) gene in schizophrenia

SAP97 gene encodes the synaptic scaffolding PDZ proteins that interact with the L: -alpha-amino-3-hydroxyl-5-methylisoxazole-4-propionate (AMPA), kainate and N-methyl-D: -aspartate (NMDA) type glutamate receptors. Because the disturbed glutamate neurotransmission has been implicated in the pathophysiology of schizophrenia, we investigated association between the SAP97 gene and schizophrenia. We genotyped 23 SNPs capturing the known common haplotype variations of the gene in a sample comprising 229 schizophrenic patients and 214 matched controls. In a single marker analysis, ten SNPs displayed nominally significant (P < 0.05) association with schizophrenia, although the P values of these SNPs were non-significant after the Bonferroni correction. We also compared haplotype estimates based on case-control genotypes and observed significant association of eight-two- and three- SNP haplotypes with schizophrenia following permutation-based correction. Further examination of the above series of SNPs or haplotypes in each gender revealed significant associations between some of these SNPs or haplotypes and the disorder only in males. The present findings suggest that the SAP97 gene may be a susceptibility factor in male schizophrenics and that the modification of the glutamate receptors-SAP97 signaling pathway could be involved in the disease pathophysiology.     

Late-onset frontotemporal dementia associated with a novel <Emphasis Type="Italic">PGRN</Emphasis> mutation

Summary We describe a new mutation in the PGRN gene (A303AfsX57) associated with late-onset frontotemporal dementia and with “cat’s eye” shaped intranuclear and cytoplasmatic ubiquitin immunoreactive inclusions in the neuropathological exam. The A303AfsX57 mutation is consistent with a nucleotide deletion in exon 8 (c908delC). This deletion causes a frameshift at codon 303 that introduces a premature termination codon (A303AfsX57).     

<Emphasis Type="Italic">Wnt</Emphasis> Pathway Anomalies in Developing Amygdalae of Turner Syndrome-like Mice

Certain neurobehavioral deficiencies associated with Turner Syndrome have been attributed to brain volumetric abnormalities, particularly of the amygdala. Haplo-insufficiency of a non-dosage compensated gene or genes on the X chromosome has been hypothesized to be the cause of the neuroanatomical defect. We examined gene expression levels of 6,628 genes in developing amygdalae of late-stage embryos of a mouse model for Turner Syndrome. In total, 161 genes show significant differences in expression level between TS and normal female amygdala. In silico pathway analysis of both X-linked and autosomal mis-regulated genes suggests that modulation of Wnt signaling is a critical factor in the normal growth and development of the amygdala. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

<Emphasis Type="Italic">c</Emphasis><Emphasis Type="Italic">-MYC</Emphasis> amplification and expression in astrocytic tumors

Point mutations and genomic multiplications in the α-synuclein (αSYN) gene cause autosomal-dominant Parkinson’s disease. Moreover, αSYN fibrils are the major component of Lewy bodies, the neuropathological hallmarks of Parkinson’s disease and dementia with Lewy bodies as well as of glial cytoplasmic inclusions in multiple system atrophy. These diseases are collectively referred to as α-synucleinopathies. Cellular mechanisms regulating αSYN fibril formation and toxicity are intensely studied in vitro, and in cell culture and diverse animal models. Specific neuropathology was achieved in transgenic mouse models using several promoters to express human wild-type and mutant αSYN in brain regions affected by the various α-synucleinopathies. Somatodendritic accumulation of the transgenic αSYN with neuritic distortions was a common finding. The nigrostriatal dopaminergic projections were surprisingly resistant to α-synucleinopathy in transgenic mice, although they tended to be more vulnerable to neurotoxins. In a few mouse models, αSYN aggregated in an age-dependent manner into genuine fibrillar amyloid. Brain region selective αSYN neuropathology correlated with specific behavioral impairments, such as locomotor dysfunction and cognitive decline. Thus, the αSYN fibrillization process is tightly linked to neuropathology. The role and thus therapeutic potential of post-translational modifications (ubiquitinylation, oxidation, phosphorylation, truncation) and modifier genes on αSYN neuropathology can now be assessed in valid transgenic mouse models of α-synucleinopathies.     

Association study on the mitochondrial gene <Emphasis Type="Italic">NDUFV2</Emphasis> and bipolar disorder in the Chinese Han population

Bipolar disorder is known to be subject to maternal transmission. Mitochondrial DNA has been suggested as playing a role in the illness. NDUFV2, located on 18p11.31-p11.2, encodes an important subunit of mitochondrial NADH (complex I). Previous studies have reported the association of NDUFV2 with bipolar disorder in the Japanese and Caucasian populations. Whether it is also a susceptible gene in the Chinese population is unknown. To study the role of NDUFV2 in bipolar disorder in the Chinese population, 506 unrelated bipolar patients and 507 unrelated controls of Chinese Han origin were recruited. Six SNPs (rs11661859, rs6506640, rs1156044, rs4148965, rs906807, rs977581) were genotyped using either TaqMan^® technology or direct sequencing. The haplotype consisting of rs6506640 (?342G > A) and rs906807 (86C > T) was found to be associated with bipolar disorder (global p = 0.012 before corrected, p = 0.030 after 10,000 permutations; individual p (A–T of rs6506640–rs906807) = 0.014 after 100,000 permutations (p = 0.0065 before corrected). The genotype frequency of rs906807 differed between bipolar female patients and female controls (p = 0.012, uncorrected). No other individual associations of SNPs with bipolar were detected. Our study indicated that the regions spanning from the promoter to the exon 2 may contain susceptible polymorphisms which predispose to bipolar disorder.     

Failure to confirm an association between <Emphasis Type="Italic">Epsin 4</Emphasis> and schizophrenia in a Japanese population

Previous studies suggested that genetic variations in the 5' region of Epsin 4, a gene encoding enthoprotin on chromosome 5q33, are associated with schizophrenia. However, conflicting results have also been reported. We examined the possible association in a Japanese sample of 354 patients and 365 controls. Seventeen polymorphisms of Epsin 4 [3 microsatellites and 14 single nucleotide polymorphisms (SNPs)] were selected. A microsatellite marker (D5S1403) demonstrated a significant difference in the allele frequency between patients and controls (uncorrected P = 0.04). However, there was no significant difference in the genotype or allele frequency between the two groups for the other microsatellites or SNPs. Haplotype-based analysis provided no evidence for an association. The positive result at D5S1403 no longer reached statistical significance when multiple testing was taken into consideration. Our results suggest that the examined region of Epsin 4 does not have a major influence on susceptibility to schizophrenia in Japanese.