The Age at Motor Symptoms Onset in <Emphasis Type="Italic">LRRK2</Emphasis>-Associated Parkinson's Disease is Affected by a Variation in the <Emphasis Type="Italic">MAPT</Emphasis> Locus: A Possible Interaction

The current paradigm on Parkinson's disease (PD) pathogenesis and course suggests the involvement of multiple genes and the interaction between them. Recently, it was reported that a variation (rs2435207) in the MAPT gene region influenced the age of motor symptoms onset (AO) in 44 PD patients from 19 families, carriers of leucine-rich repeat kinase 2 (LRRK2) mutations, all of European and North American origin. To examine whether genetic factors within the MAPT locus exert a similar effect on AO in a different population of LRRK2-associated PD patients, 99 unrelated Ashkenazi patients with the LRRK2 p.G2019S mutation were analyzed. Three SNPs in the MAPT region were studied, rs393152, rs2435207, and rs11079727; the latter is located in the first intron of MAPT. Among carriers of the single LRRK2 p.G2019S mutation that did not carry a founder Ashkenazi GBA mutation too (n = 84), the AO in minor rs11079727 A allele carriers (C/A genotype) was significantly older (62.5 ± 10.6 years) compared to the AO (55.7 ± 11.6) among carriers of the C/C genotype (p = 0.025). Our results further support a possible interaction between genetic factors in the MAPT region and the LRRK2 gene, which influence the clinical course of PD patients.     

LRRK2 and GBA mutations differentially affect the initial presentation of Parkinson disease

GBA and LRRK2 mutations increase susceptibility to Parkinson disease (PD), which is characterized by various disabling symptoms. An extended cohort of 600 Ashkenazi PD patients was screened for the LRRK2 G2019S and for eight GBA mutations. Reported initial symptoms were compared between three genotypic groups of patients: carriers of GBA mutations, carriers of LRRK2 G2019S mutation, and non-carriers. More LRRK2 G2019S carriers reported muscle stiffness (rigidity, p = 0.007) and balance disturbances (p = 0.008), while more GBA mutation carriers reported slowness (bradykinesia, p = 0.021). These results suggest distinct effects of LRRK2 or GBA mutations on the initial symptoms of PD.     

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).     

<Emphasis Type="Italic">OPCML</Emphasis> Gene as a Schizophrenia Susceptibility Locus in Thai Population

Opioid-binding protein/cell adhesion molecule (OPCML) gene has been recently identified as a susceptibility gene for schizophrenia in Europeans. This study aims to investigate the association between single nucleotide polymorphisms (SNPs) in the OPCML gene and risk of schizophrenia in a Thai population. DNA samples of 115 schizophrenia patients and 173 normal controls were genotyped using high-resolution melting analysis and analyzed by chi-square test of SPSS software. We observed a strong association between an intronic SNP of the OPCML gene (rs1784519) and the risk of schizophrenia in the Thai population [P = 0.00036; odds ratio for the minor A allele, 2.11(1.57–2.84)]. The previously discovered SNP associated with schizophrenia in Europeans, rs3016384, also showed significant association with schizophrenia in the Thai population [P = 0.01; odds ratio of the minor T allele, 0.59 (0.44–0.79)]. Therefore, the OPCML gene is considered to be a schizophrenia-susceptible gene in the Thai population.     

Mutation analysis of the Ras pathway genes<Emphasis Type="Italic"> NRAS</Emphasis>,<Emphasis Type="Italic"> HRAS</Emphasis>,<Emphasis Type="Italic"> KRAS</Emphasis> and<Emphasis Type="Italic"> BRAF</Emphasis> in glioblastomas

Aberrant activation of Ras signaling is a common finding in human glioblastomas. To determine the contribution of Ras gene mutations to this aberration, we screened 94 glioblastomas for mutations in the three Ras family genes NRAS, KRAS and HRAS. All tumors were additionally analyzed for mutations in BRAF, which encodes a Ras-regulated serine/threonine kinase with oncogenic properties. Mutation analysis of the entire coding regions of NRAS and KRAS, as well as the known mutation hot-spot sites in HRAS, identified somatic point mutations in two glioblastomas, both affecting codon 12 of NRAS (c.35G>A, p.G12D). Three additional tumors carried BRAF mutations altering the known hot-spot codon 599 (c.1796T>A, p.V599E). None of these five glioblastomas showed amplification of the EGFR or PDGFRA genes, while three of the tumors, including two with NRAS and one with BRAF mutation, demonstrated PTEN missense mutations or loss of PTEN mRNA expression. Taken together, our data suggest activating mutations in NRAS or BRAF as a molecular alteration that contributes to aberrant Ras signaling in a small fraction of glioblastomas.     

<Emphasis Type="Italic">PEMT</Emphasis> G523A (V175M) Is Associated with Sporadic Alzheimer's Disease in a Chinese Population

There is evidence that increased concentrations of circulating homocysteine are associated with Alzheimer's disease (AD). Phosphatidylethanolamine N-methyltransferase (PEMT) is an important catalyst involved in the production of homocysteine. We investigated the association of a functional single nucleotide polymorphism (rs7946) in PEMT with sporadic AD risk in a Han Chinese population that included 386 AD patients and 366 controls. PEMT G523A was genotyped by either sequencing or PCR-restriction fragment length polymorphism analysis. The plasma homocysteine concentrations of 210 subjects were determined by high-performance liquid chromatography. Significant higher frequency of the A allele was detected in AD cases than in controls (A vs. G, p = 0.007, OR = 1.482, 95% CI 1.114–1.972). After adjusting for gender, age/age at onset, and APOE ε4 status, logistic analysis showed rs7946 was associated with AD in a dominant model (AA + GA vs. GG, p = 0.007, OR = 1.596, 95% CI 1.138–2.240). When stratified by APOE ε4 status or gender, the significant difference was only observed in the APOE ε4 non-carriers and in the female subjects, respectively. We did not find a relationship of this polymorphism with plasma homocysteine levels. These results suggested that PEMT G523A is associated with AD and that the A allele is an APOE ε4-independent risk factor for AD among Han Chinese women.     

<Emphasis Type="Italic">CIC</Emphasis> and <Emphasis Type="Italic">FUBP1</Emphasis> mutations in oligodendrogliomas,oligoastrocytomas and astrocytomas

CIC and FUBP1 mutations have recently been detected in oligodendrogliomas but not in oligoastrocytomas. However, allelic losses in the regions on chromosomal arms 19q and 1p harboring CIC and FUBP1 are a common feature of both, oligodendrogliomas and oligoastrocytomas. To resolve this discrepancy, we analyzed CIC and FUBP1 mutations in a set of primary brain tumors including 18 oligodendrogliomas and 42 oligoastrocytomas. In addition, we analyzed 10 astrocytomas and 16 glioblastomas with allelic losses on 19q as well as a set of 12 medulloblastomas for CIC mutations. CIC mutations were found in 15/18 oligodendrogliomas, 14/42 oligoastrocytomas and 3/10 preselected astrocytomas. With the exception of a single case, all CIC mutations occurred in tumors with combined 1p/19q losses. In contrast to oligodendrogliomas where CIC mutations were always detected along with 1p/19q co-deletion, CIC mutations were only found in 52 % of the 1p/19q co-deleted oligoastrocytomas. FUBP1 mutations were detected in 7/61 tumors, all presenting with CIC mutations. FUBP1 mutations appear to cluster in the DNA binding domain spanning exons 5–14. CIC and FUBP1 mutations exclusively occurred in presence of either IDH1 or IDH2 mutations. Our data confirm CIC and FUBP1 mutations in oligodendrogliomas and demonstrate the presence of these mutations in oligoastrocytomas.     

Mutation screening of <Emphasis Type="Italic">mitofusin 2</Emphasis> in Charcot-Marie-Tooth disease type 2

Charcot-Marie-Tooth (CMT) disease is among the most common inherited neurological disorders. Mutations in the gene mitofusin 2 (MFN2) cause the axonal subtype CMT2A, which has also been shown to be associated with optic atrophy, clinical signs of first motor neuron involvement, and early onset stroke. Mutations in MFN2 account for up to 20–30% of all axonal CMT type 2 cases. To further investigate the prevalence of MFN2 mutations and to add to the genotypic spectrum, we sequenced all exons of MFN2 in a cohort of 39 CMT2 patients. We identified seven variants, four of which are novel. One previously described change was co-inherited with a PMP22 duplication, which itself causes the demyelinating form CMT1A. Another mutation was a novel in frame deletion, which is a rare occurrence in the genotypic spectrum of MFN2 characterized mainly by missense mutations. Our results confirm a MFN2 mutation rate of ~15–20% in CMT2.     

Substantia nigra hyperechogenicity correlates with clinical status and number of <Emphasis Type="Italic">Parkin</Emphasis> mutated alleles

To further evaluate (1) transcranial sonography (TCS) for (pre)clinical diagnosis of Parkinson's disease (PD) and (2) to examine asymptomatic carriers of Parkin mutations we investigated substantia nigra (SN) hyperechogenicity in PD patients and unaffected subjects with and without Parkin mutations. The area (aSN) of the hyperechogenic SN were calculated bilaterally and study subjects were assigned to high versus low value groups. Eleven of the (affected and unaffected) mutation carriers had previously undergone 18-fluoro-dopa-(FDOPA)-PET scans. Fifty-eight individuals were investigated, including 24 with clinically definite and 34 without symptoms or signs of PD. Of the patients, three had one mutated and six had two mutated Parkin alleles. Of the unaffected subjects, 13 carried a single Parkin mutated allele. After dichotomization, 21 subjects had high and 37 subjects low values of mean aSN. Regarding the clinical status, 13 (62%) of the individuals with a high mean aSN had PD,while 26 (70%) of the study subjects with low values did not show signs of PD (p = 0.0393). Similarly, probands with high mean aSN values more frequently carried Parkin mutations (58%) than probands with low values (27%, p = 0.0234). A negative correlation between FDOPA uptake in the posterior putamen and maximum aSN was found in the group of mutation carriers (r = –0.809, p = 0.0234). In conclusion, hyperechogenicity of the SN is found in both idiopathic and Parkin-associated PD. Further strengthening the notion of a potential relationship between SN hyperechogenicity and Parkin mutational status, a larger aSN was associated with an increasing number of mutated alleles in our study. The authors have no financial or other interests to disclose.     

Selective acquisition of <Emphasis Type="Italic">IDH1</Emphasis> R132C mutations in astrocytomas associated with Li-Fraumeni syndrome

Mutations of the IDH1 gene are frequent in gliomas, with R132H (CGT → CAT) being the most common (>85%). In astrocytomas, IDH1 mutations are typically co-present with, or precede, TP53 mutations. We assessed IDH1 mutations in brain tumors diagnosed in patients from three families with Li-Fraumeni syndrome. We identified IDH1 mutations in five astrocytomas that developed in carriers of a TP53 germline mutation. Without exception, all were R132C (CGT → TGT), which in sporadic astrocytomas accounts for <5% of IDH1 mutations. This remarkably selective occurrence of R132C mutations may reflect differences in the sequence of genetic events, with a preference for R132C mutations in astrocytes or precursor cells that already carry a germline TP53 mutation.     

Influence of CagA-positive <Emphasis Type="Italic">Helicobacter pylori</Emphasis> strains on atherosclerotic carotid disease

Citotoxin-associated gene-A (CagA)-positive Helicobacter pylori strains have been associated with occurrence and destabilization of coronary atherosclerotic plaques. However, data on the relationship between CagA-positive H. pylori infection and carotid artery instability are lacking. Thus, the role of CagA antigen in patients with symptomatic and asymptomatic carotid atherosclerotic plaques was investigated. A total of 64 patients with advanced carotid artery stenosis, including 33 patients with symptomatic and 31 patients with asymptomatic internal carotid artery stenosis, verified by duplex ultrasound, all undergoing carotid endarterectomy, were studied. The control group consisted of 65 subjects without a history or presence of vascular diseases. Serology for H. pylori and CagA antigen was assessed in all participants. Specimens of atherosclerotic plaques obtained from all patients during carotid endarterectomy were analyzed immunohistochemically using anti-CagA monoclonal antibodies. The ultrasonographic plaque characteristics were also estimated. CagA antibody titers were significantly higher in symptomatic patients (8.8; range, 5.8–32.7) compared to asymptomatic patients (4.7; range, 2.1–8.8; P = 0.005) and the control group (5.0; range 2.2–7.9; P < 0.001). There was significant difference in echolucency (≥25% soft material) between the symptomatic and asymptomatic groups (P = 0.034) by ultrasonographic evaluation. Positive immunoreactivity between monoclonal CagA antibodies and antigens within atherosclerotic specimens was significantly higher among symptomatic patients compared to asymptomatic patients (97.0 vs. 74.2%; P = 0.009). H. pylori may play a role in the pathogenesis of the atherosclerotic process due to autoimmune mechanisms and even contribute to destabilization of carotid atherosclerotic plaques.     

In cis autosomal dominant mutation of <Emphasis Type="Italic">Senataxin</Emphasis> associated with tremor/ataxia syndrome

Senataxin mutations are the molecular basis of two distinct syndromes: (1) ataxia oculomotor apraxia type 2 (AOA2) and (2) juvenile amyotrophic lateral sclerosis 4 (ALS4). The authors describe clinical and molecular genetic studies of mother and daughter who display symptoms of cerebellar ataxia/atrophy, oculomotor defects, and tremor. Both patients share Senataxin mutations N603D and Q653K in cis (N603D–Q653K), adjacent to an N-terminal domain thought to function in protein–protein interaction. The N-terminal and helicase domains appear to harbor missense mutation clusters associated with AOA2 and ALS4. Working synergistically, the N603D–Q653K mutations may confer a partial dominant negative effect, acting on the senataxin N-terminal, further expanding the phenotypic spectrum associated with Senataxin mutations.     

Symmetrical Corticobasal Syndrome Caused by a Novel c.314dup <Emphasis Type="Italic">Progranulin</Emphasis> Mutation

Corticobasal syndrome (CBS) is characterised by asymmetrical parkinsonism and cognitive impairment. The underlying pathology varies between corticobasal degeneration, progressive supranuclear palsy, Alzheimer’s disease, Creutzfeldt–Jakob disease and frontotemporal lobar degeneration sometimes in association with GRN mutations. A 61-year-old male underwent neurological examination, neuropsychological assessment, MRI, and HMPAO-SPECT at our medical centre. After his death at the age of 63, brain autopsy, genetic screening and mRNA expression analysis were performed. The patient presented with slow progressive walking disabilities, non-fluent language problems, behavioural changes and forgetfulness. His family history was negative. He had primitive reflexes, rigidity of his arms and postural instability. Later in the disease course he developed dystonia of his left leg, pathological crying, mutism and dysphagia. Neuropsychological assessment revealed prominent ideomotor and ideational apraxia, executive dysfunction, non-fluent aphasia and memory deficits. Neuroimaging showed symmetrical predominant frontoparietal atrophy and hypoperfusion. Frontotemporal lobar degeneration (FTLD)-TDP type 3 pathology was found at autopsy. GRN sequencing revealed a novel frameshift mutation c.314dup, p.Cys105fs and GRN mRNA levels showed a 50% decrease. We found a novel GRN mutation in a patient with an atypical (CBS) presentation with symmetric neuroimaging findings. GRN mutations are an important cause of CBS associated with FTLD-TDP type 3 pathology, sometimes in sporadic cases. Screening for GRN mutations should also be considered in CBS patients without a positive family history.     

A novel <Emphasis Type="Italic">mitofusin 2</Emphasis> mutation causes canine fetal-onset neuroaxonal dystrophy

We recently reported autosomal recessive fetal-onset neuroaxonal dystrophy (FNAD) in a large family of dogs that is not caused by mutation in the PLA2G6 locus (Fyfe et al., J Comp Neurol 518:3771–3784, 2010). Here, we report a genome-wide linkage analysis using 333 microsatellite markers to map canine FNAD to the telomeric end of chromosome 2. The interval of zero recombination was refined by single-nucleotide polymorphism (SNP) haplotype analysis to ~200 kb, and the included genes were sequenced. We found a homozygous 3-nucleotide deletion in exon 14 of mitofusin 2 (MFN2), predicting loss of a glutamate residue at position 539 in the protein of affected dogs. RT-PCR demonstrated near normal expression of the mutant mRNA, but MFN2 expression was undetectable to very low on western blots of affected dog brainstem, cerebrum, kidney, and cultured fibroblasts and by immunohistochemistry on brainstem sections. MFN2 is a multifunctional, membrane-bound GTPase of mitochondria and endoplasmic reticulum most commonly associated with human Charcot–Marie–Tooth disease type 2A2. The canine disorder extends the range of MFN2-associated phenotypes and suggests MFN2 as a candidate gene for rare cases of human FNAD.     

Significant association of the <Emphasis Type="Italic">arylalkylamine N-acetyltransferase</Emphasis> (<Emphasis Type="Italic">AA-NAT</Emphasis>) gene with delayed sleep phase syndrome

Arylalkylamine N-acetyltransferase (AA-NAT) is a rate-limiting enzyme in melatonin hormone synthesis and participates in daily oscillations of the melatonin level. We studied the association between the AA-NAT gene and delayed sleep phase syndrome (DSPS). Results indicate that there is a significant difference in allele positivity at the single nucleotide polymorphism involved in an amino acid substitution from alanine to threonine at position 129 between patients with DSPS and healthy controls. The frequency of the 129 threonine allele is significantly higher in the patients than in the controls (P=0.0029). The data suggest that AA-NAT could be a susceptibility gene for DSPS. Electronic Publication     

High frequency stimulation of the subthalamic nucleus is efficacious in <Emphasis Type="Italic">Parkin</Emphasis> disease

Abstract High frequency stimulation (HFS) of the subthalamic nucleus (STN) is an efficacious symptomatic treatment for Parkinsons disease. We have analysed the genetic status of a series of consecutive parkinsonian patients implanted for STN HFS and compared the outcome of five carrying mutations in the parkin gene with that of the non-parkin group. All patients obtained sustained control of PD symptoms and achieved functional improvement; in the parkin group the UPDRS motor score improved by 56.4%, the levodopa equivalent daily dosage was reduced by 75.5%. Postoperative medications were reduced more in parkin than in non-parkin patients. We confirm that the current inclusion criteria for STN HFS do not exclude patients carrying mutations in the parkin gene; their clinical outcome is comparable to that of the non-parkin group.     

Neuroprotective properties of<Emphasis Type="Italic">Valeriana officinalis</Emphasis> extracts

Valeriana officinalis have been used in traditional medicine for its sedative, hypnotic, and anticonvulsant effects. There are several eports in the literature supporting a GABAergic mechanism of action for valerian. The rationale of the present work is based on the concept that by decreasing neuronal network excitability valerian consumption may contribute to neuroprotection. The aim of our investigation was to evaluate the neuroprotective effects ofV. officinalis against the toxicity induced by amyloid beta peptide 25–35 [Aβ_(25–35)]. Cultured rat hip-pocampal neurons were exposed to Aβ_(25–35)(25 μM) for 24–48 h,after which morphological and biochemical properties were evaluated. The neuronal injury evoked by Aβ, which includes a decrease in cell educing capacity and associated neuronal degeneration, was prevented by valerian extract. Analysis of intracellular free calcium ([Ca²⁺]_i)indicated that the neuroprotective mechanisms may involve the inhibition of excess influx of Ca²⁺ following neuronal injury. Moreover, membrane peroxidation in rat hippocampal synaptosomes was evaluated, and our data indicate that valerian extract partially inhibited ascorbate/iron-induced peroxidation. In conclusion we show evidence that the signalling pathways involving [Ca²⁺]_i and the redox state of the cells may play a central ole in the neuroprotective properties ofV. officinalis extract against Aβ toxicity. The novelty of the findings of the present work, indicating neuroprotective properties of valerian against Aβ toxicity may, at the long-term, contribute to introduction of a new elevant use of valerian alcoholic extract to prevent neuronal degeneration in aging or neurodegenerative disorders.     

A neuropathological study of autosomal-dominant chorea-acanthocytosis with a mutation of <Emphasis Type="Italic">VPS13A</Emphasis>

We report the first autopsy case of genetically confirmed, autosomal-dominant chorea-acanthocytosis (AD-ChAc), showing a heterozygous mutation (G–A) at nucleotide position 8,295 in exon 57 of VPS13A. The patient was a 36-year-old Japanese man and the duration of his illness was 11 years. Neuropathologically, the patient showed marked atrophy and neuronal loss, particularly small and medium-sized neurons, with astrocytic gliosis in the caudate nucleus, putamen and globus pallidus. These findings were similar to previous autopsy reports of autosomal-recessive ChAc (AR-ChAc) with mutations of VPS13A. The broad distribution of atrophic neurons and astrocytosis throughout the whole brain was unique in our AD-ChAc patient and has not been described in AR-ChAc. The neuronal density of the dorsal caudate nucleus was lower than that of the ventral side in this patient as well as in three Huntington’s disease (HD) patients. The neuronal densities in both the rostral and caudal sides were lower than that in the middle region at the anterior commissure level, while in the three HD patients, the neuronal densities of the caudate nucleus were more decreased in the caudal side. This ChAc patient showed faint immunoreactivity in the caudate nucleus and globus pallidus with antibodies against the striatal neurotransmitters, methionine–enkephalin, leucine–enkephalin and substance P. The difference in patterns of neuronal vulnerability could reflect those in the mechanisms of neurodegeneration between ChAc and HD.     

The Nonsynonymous Thr105Ile Polymorphism of the Histamine <Emphasis Type="Italic">N</Emphasis>-Methyltransferase is Associated to the Risk of Developing Essential Tremor

Objective We analyzed in patients with essential tremor (ET) the Thr105Ile polymorphism of the Histamine N-methyltransferase (HNMT) enzyme that is associated to Parkinson’s disease (PD) risk. Methods Leukocytary DNA from 204 ET patients and a control group of 295 unrelated healthy individuals was studied for the nonsynonymous HNMT Thr105Ile polymorphism by using amplification-restriction analyses. Results Patients with ET showed a higher frequency of homozygous HNMT 105Thr genotypes leading to high metabolic activity (p < 0.015) with a statistically significant gene-dose effect, as compared to healthy subjects. These findings were independent of gender, and of tremor localization, but the association of the HNMT polymorphism is more prominent among patients with late-onset ET (p < 0.007). Conclusion These results, combined with previous findings indicating alterations in the frequency for the HNMT Thr105Ile polymorphism in patients with PD, suggest that alterations of histamine homeostasis in the SNC are associated with the risk of movement disorders.