Mutation analysis of Parkin, PINK1 and DJ-1 genes in Chinese patients with sporadic early onset parkinsonism

Early onset parkinsonism (EOP) has been associated with mutations in the Parkin, PINK1, and DJ-1 genes. We studied the prevalence of mutations in all three genes in 127 unrelated Chinese patients with apparently sporadic EOP using direct sequencing analysis and real-time quantitative PCR analysis assay. There are 16 patients (12.6%) with mutations of Parkin gene, four patients (3.1%) with mutations of PINK1 gene, and three patients (2.4%) with mutation of DJ-1 gene. In conclusion, Parkin gene mutation is the most common pathogenic factor in Chinese patients with sporadic EOP. Mutations of DJ-1 and PINK1 gene are also found in Chinese patients with sporadic EOP.     

Genetic analysis of the alpha2-macroglobulin gene in early- and late-onset Parkinson's disease

Recent association studies investigating polymorphisms in the alpha2-macroglobulin (A2M) gene provided evidence for an involvement of this protease inhibitor in the pathogenesis of Alzheimer's disease (AD). The partially overlapping pathology between AD and Parkinson's disease (PD) led us to investigate the role of A2M in PD. We performed association studies in a large sample of 328 German PD patients and 322 closely matched healthy controls. Analyzing the Val1000Ile polymorphism and a pentanucleotide deletion in the 5' splice site of exon 18 of the A2M gene we found an excess of homozygosity for the A2M deletion in early-onset PD (EOPD) patients (age at onset < 50 years) compared to late-onset PD (LOPD) patients (age at onset > 50 years; p = 0.008, p(p)c = 0.064, chi2 = 7.017). Therefore our data might indicate an age at onset modulating effect of the homozygous A2M deletion in PD.     

PINK1 mutation in Taiwanese early-onset parkinsonism

Abstract The PINK1 gene mutation is probably the second most common genetic cause of early-onset Parkinson's disease (EOPD). The frequency and the characteristics of the PINK1 mutation in the Taiwanese population are unknown. This study was designed to investigate the genotype, phenotype and dopaminergic function of PINK1 in a cohort of EOPD patients. The genetic settings were to detect the PINK1 gene mutations in 138 EOPD patients and in 191 controls. Using the ^99mTc-TRODAT-1 (TRODAT) scan, we investigated the differences in the dopamine transporter (DAT) activities between the PINK1 patients, late-onset Parkinson's disease (LOPD) patients and healthy controls. Four EOPD patients with 3 genotypic mutations in the PINK1 gene were found: a compound heterozygous mutation (Q239X/R492X) in 2 sisters, a novel homozygous mutation (R492X) in a woman, and a novel heterozygous mutation (G193R) in a man. The three PINK1 patients had typical phenotype with juvenile onset, benign course, and frequently with dyskinesias. The TRODAT scan showed a rather even and symmetrical reduction of uptake in PINK1 patients, unlike the dominant decline in the putamen in the LOPD patients. The annual reduction rate of uptake in the striatum was much slower in PINK1 patients than that in the LOPD patients (1.7 % vs. 4.1%; p<0.005). In the patient with a heterozygous mutation in the PINK1 gene, the reduction ratio in the striatum, as well as the annual reduction rate, were closer to those in the LOPD group. We conclude that the incidence of carrying PINK1 mutations in the present cohort of Taiwanese EOPD patients was low, accounting for 2/39 (5.1 %) in familial cases, and 2/99 (2 %) in sporadic cases. The slower annual reduction of DAT activity might indicate the insidious degeneration of dopamine neurons and a benign prognosis.     

Novel PINK1 mutations in early-onset parkinsonism

PINK1 was recently found to be associated with PARK6 as the causative gene. We performed mutation analysis in eight inbred families whose haplotypes link to the PARK6 region. We identified six pathogenic mutations (R246X, H271Q, E417G, L347P, and Q239X/R492X) in six unrelated families. All sites of mutations were novel, suggesting that PINK1 may be the second most common causative gene next to parkin in parkinsonism with the recessive mode of inheritance.     

PINK1 mutations are associated with sporadic early-onset parkinsonism

We have recently reported homozygous mutations in the PINK1 gene in three consanguineous families with early-onset parkinsonism (EOP) linked to the PARK6 locus. To further evaluate the pathogenic role of PINK1 in EOP and to draw genotype-phenotype correlates, we performed PINK1 mutation analysis in a cohort of Italian EOP patients, mostly sporadic, with onset younger than 50 years of age. Seven of 100 patients carried missense mutations in PINK1. Two patients had two PINK1 mutations, whereas in five patients only one mutation was identified. Age at onset was in the fourth-fifth decade (range, 37-47 years). The clinical picture was characterized by a typical parkinsonian phenotype with asymmetric onset and rare occurrence of atypical features. Slow progression and excellent response to levodopa were observed in all subject. Two of 200 healthy control individuals also carried one heterozygous missense mutation. The identification of a higher number of patients (5%) than controls (1%) carrying a single heterozygous mutation, along with previous positron emission tomography studies demonstrating a preclinical nigrostriatal dysfunction in PARK6 carriers, supports the hypothesis that haploinsufficiency of PINK1, as well as of other EOP genes, may represent a susceptibility factor toward parkinsonism. However, the pathogenetic significance of heterozygous PINK1 mutations still remains to be clarified.     

帕金森病PINK1基因T313M的突变分析

目的 筛查中国帕金森病患者是否存在PINK1基因T313M错义突变.方法 应用聚合酶链反应(PCR)、DNA测序和限制性片段长度多态性(RFLP)等技术对1个帕金森病家系及120例散发性帕金森病患者进行PINK1基因T313M的突变分析.结果 在一个家系中检测出PINK1基因T313M错义突变:3例患者为突变纯合子,患者母亲为杂合子,先症者1例临床表型正常的同胞也为突变纯合子(症状前患者);120例散发性帕金森病患者中未发现T31 3M突变.3例患者均表现有静止性震颤、肌强直;症状有波动性,睡眠后明显减轻;腱反射活跃;对美多巴反应良好.结论 PINK1基因T313M错义突变不大可能是中国散发性帕金森病患者的突变热点.     

帕金森病PINK1基因R492X突变分析

目的 筛查中国帕金森病患者是否存在PINK1基因R492X无义突变.方法 应用聚合酶链反应(PCR)、DNA测序和限制性片段长度多态性(RFLP)等技术对1个帕金森病家系及120例散发性帕金森病患者进行PINK1基因R492X的突变分析.结果 在一个家系中检测出PINK1基因R492X无义突变:患者为突变纯合子,患者父母为杂合子;120例散发性帕金森病患者中未发现R492X突变.结论 PINK1基因R492X无义突变不大可能是中国散发性帕金森病患者的突变热点.     

Mutation analysis of the SPG4 gene in Italian patients with pure and complicated forms of spastic paraplegia

Mutations in the SPG4 gene are the most common causes of hereditary spastic paraplegia (HSP) accounting for up to 40% of autosomal dominant (AD) forms and 12–18% of sporadic cases. The phenotype associated with HSP due to mutations in the SPG4 gene tends to be pure. There is increasing evidence, however, of patients with complicated forms of spastic paraplegia in which SPG4 mutations were identified. A cohort of 38 unrelated Italian patients with spastic paraplegia, of which 24 had a clear dominant inheritance and 14 were apparently sporadic, were screened for mutations in the SPG4 gene.We identified 11 different mutations, six of which were novel (p.Glu143GlyfsX8, p.Tyr415X, p.Asp548Asn, c.1656_1664delinsTGACCT, c.1688-3C>G and c.*2G>T) and two exon deletions previously reported. The overall rate of SPG4 gene mutation in our patients was 36.8% (14/38); in AD-HSP we observed a mutation frequency of 45.8% (11/24), in sporadic cases the frequency was 21.4% (3/14). Furthermore, we found a mutational rate of 22.2% (2/9) and 41.4% (12/29) in the complicated and pure forms, respectively. The results underlie the importance of genetic testing in all affected individuals.     

Mutation analysis of ATP13A2 in early-onset parkinsonism patients☆○

BACKGROUND： A recent study has found that ATP13A2 is the causative gene for PARK9-linked autosomal recessive early-onset parkinsonism, described previously in Jordanian and Chilean families （Kufor-Rakeb syndrome）. OBJECTIVE： To screen eastern Asian patients with early-onset parkinsonism for mutations in ATP13A2 and to describe positron emission tomography （PET） findings of PARK9-linked parkinsonism. DESIGN, TIME AND SETTING： In total, 117 patients were selected from the Department of Neurology, Juntendo University, from February 2003 to October 2006, for this molecular genetics and case-control study. PARTICIPANTS： The patients with parkinsonism consist of two cohorts. Ninety four patients with onset age of less than 30 years were selected for the first cohort. They included 49 males and 44 females, comprising 73 Japanese, 9 Korean, 8 Taiwanese, and 4 Mainland Chinese. Eleven patients had parkinsonism complicated with dementia, 15 patients had family histories of parkinsonism （including 2 families）, and 5 patients were from consanguineous parents （including one family）. The second cohort of 23 patients was composed of patients with consanguineous parents （n = 15） or who had affected siblings （n = 6） or both （n = 2）, but the age at onset ranged from 30 to 50 years. METHODS： In 117 patients with parkinsonism, direct sequencing of ATP13A2 exons 13, 16, and 26, in which mutations had been reported previously, were performed. Sequencing was also performed in all 29 exons, including splice sites, in 28 probands who showed homozygosity at the PARK9 locus by haplotype analysis. Mutation analysis was also performed in 150 normal people. Linkage analysis was performed on all 3 parkinsonism families using short tandem repeat markers flanking the PARK9 locus. For patients who had ATP13A2 mutation, we performed brain MRI and ^18F-dopa PET scans. MAIN OUTCOME MEASURES： ATP13A2 DNA sequence, ^18F-dopa PET scan and brain MRI findings. RESULTS： A novel F182L mutation in a consanguineous J     

Phenotypic differences in early- and late-onset obsessive-compulsive disorder

Early-onset forms of many medical diseases have been associated with specific genetic anomalies. To assess the potential marker value of onset age in obsessive-compulsive disorder (OCD), we examined and compared the phenotypic characteristics of patients with early and later onset. The study sample included 38 children with DSM-IV OCD and 129 adults 19 years of age or older, 77 of whom reported OCD onset prior to age 18 and 52 of whom reported OCD onset at 18 years of age or older. DSM-IV diagnoses were ascertained for all subjects using an amended version of the Diagnostic Interview for Genetic Studies (DIGS). An initial comparison of children and adults with childhood onset revealed several differences, including an earlier onset of clinically significant symptoms without impairment and earlier onset of DSM-IV OCD, a higher frequency of learning disabilities, and fewer obsessions and compulsions among our child patients. For this reason, subsequent analyses included only adult patients with early and later OCD onset. Nonimpairing symptom onset prior to puberty, a relatively aggressive course, and a greater number of obsessions and compulsions unrelated to the amount of time in illness characterized early-onset OCD. Later-onset OCD was characterized by nonimpairing symptom onset during puberty, a static course, and relatively few obsessions and compulsions that were variably related to the amount of time in illness. We conclude that children with OCD and adults with childhood onset differ in their report of clinical characteristics and should be analyzed separately in studies concerning the phenotypic characteristics of OCD. Early- and late-onset forms of OCD appear to be characterized by phenotypic features that have important neurobiologic and perhaps genetic implications.     

Neurotransmitter changes in early- and late-onset alzheimer-type dementia

Arai Heii., Yosuke Ichimiya, Kenji Kosaka, Takashi Noroji and Reiji Iizuka: Neurotransmitter Changes in Early- and Late-onset Alzheimer-type Dementia. Prog. Neuro-Psychophamacol. & Biol. Psychiat. 1992, 16(6):883–890.

1. 1. Neurotransmitter-related markers were examined in Alzheimer-type dementia (ATD) and studied whether or not there is biochemical difference between the early- and late-onset sub-groups.

2. 2. Postmortem brains were obtained from neuropathologically diagnosed ATD patients and control subjects with no clinico-neuropathological findings indicative of neuropsychiatric diseases.

3. 3. Neurochemical data in the early- and late-onset groups were compared to the age-matched younger and older control groups, respectively, and expressed as a percentage of the mean value in the respective controls.

4. 4. Choline acetyltransferase activity and concentrations of serotonin and noradrenaline were more severely depleted in the early-onset ATD group than in the late-onset ATD group.

5. 5. These findings indicative of heterogeneity of ATD patients were discussed from the pathogenetic and therapeutic viewpoints.

Neuropsychological functioning in early- and late-onset obsessive-compulsive disorder

Significant relationships have been noted between age of onset and demographics, clinical characteristics, and cerebral metabolic activity in obsessive-compulsive disorder (OCD). The authors investigated whether patients with early (N=21) and late (N=17) onset OCD differ with respect to neuropsychological functioning. Results revealed that the late onset OCD group obtained poorer scores on measures of executive function and auditory attention than the early onset group. Late onset OCD was also associated with poorer visual memory relative to healthy comparison subjects. These findings suggest that early and late onset OCD may be the result of at least partially differing neurobiological mechanisms.     

结节性硬化症TSC1基因编码外显子全长的突变检测与分析

目的研究结节性硬化症(TSC)TSC1基因所有编码外显子的基因突变特征和多态现象。方法采用聚合酶链反应单链构象多态(PCR SSCP)技术结合DNA测序对来源于21个家系的23例TSC患者、22名父母及60名健康对照进行TSC1基因编码外显子全长的基因突变和多态的检测。结果共检测出10种异常的SSCP带型,经DNA测序后证实为4种突变和6种多态,突变包括2种移码突变(352insA和2332insT)、1种剪接突变(729 1G→T)、1种无义突变Tyr761Ter(2504C→A),其中2332insT, 729 1G→T及Tyr761Ter为新型突变。以上突变均见于散发型患者,突变频率为4 /15。6种多态包括4种单核苷酸多态(347A→C, 1186T→C, 1556A→G, 1947T→C), 1种内含子区多态(2218 71delAG)及1种3′UTR区多态(3716 36T→C),其中3种为新多态。结论本组结果对研究我国TSC1基因突变特征提供了重要资料,未发现TSC1基因突变热区,且TSC1基因突变多见于散发型患者,提示中西方TSC1基因突变可能存在差异。     

Clinicogenetic study of PINK1 mutations in autosomal recessive early-onset parkinsonism

The authors performed PINK1 mutation analysis of 51 families with autosomal recessive Parkinson disease (ARPD). They found two novel PINK1 mutations: one was a homozygous deletion (13516-18118del) and the other a homozygous missense mutation (C388R). Clinically, the patients with the deletion had dementia. Thus, early-onset PD with dementia may be considered PINK1-linked parkinsonism. Furthermore, patients with PINK1 mutations form 8.9% of parkin- and DJ-1-negative ARPD families.     

Monocular horizontal OKN in observers with early- and late-onset strabismus.

Several reports on monocular optokinetic nystagmus (OKN) in observers with strabismus have found that asymmetry of OKN tends to occur in both eyes of observers with an early onset of strabismus but only in the deviating eye of those with a later onset of strabismus. Our objective was to quantify and compare the magnitude of the OKN asymmetry in each eye as a function of observer's age at onset of strabismus. We studied monocular OKN in ten observers with early-onset (up to 24 months of age), seven observers with late-onset (after 24 months of age) unilateral strabismus, and 12 normally sighted control observers. In the deviating eye, observers with early-onset strabismus showed large OKN asymmetries in favour of nasalward motion while observers with late-onset strabismus showed smaller OKN asymmetries in that eye. The majority of early- and late-onset observers showed near normal OKN in the non-deviating eye although the early-onset observers showed bilateral asymmetries more often. These findings may be due to both age at onset of strabismus and chronological age and are discussed in terms of the issue of plasticity or recovery of function.