Screening for LRRK2 mutations in patients with Parkinson's disease in Russia: identification of a novel LRRK2 variant

Background and purpose:  Mutations in LRRK2 , encoding leucine-rich repeat kinase 2 (or Dardarin), cause autosomal dominant Parkinson's disease (AdPD) and are also found in sporadic PD (sPD). To investigate the frequency of LRRK2 mutations in a sample of Russian PD patients.
Methods:  We sequenced the complete coding region of LRRK2 in 65 patients with AdPD and in 30 patients with sPD. Furthermore, in 20 patients with AdPD and in 159 patients with sPD we screened several common LRRK2 mutations (G2019S, R1441C/G/H, I2012T and I2020T).
Results:  Five AdPD patients had the LRRK2 G2019S mutation (5.9%, 5/85). In addition, we discovered a novel LRRK2 variant V1613A in a family with a tremor dominant form of AdPD; this variant was not present in controls. We identified two patients with LRRK2 mutations in sPD: one with the G2019S mutation (0.5; 1/189) and another with the previously described R1441C mutation (0,5; 1/189).
Conclusions:  LRRK2 mutations are common amongst patients with PD in Russia. The results also show that the G2019S mutation is the most frequent. We identified one novel mutation in a functional region of LRRK2.     

Prevalence and clinical features of LRRK2 mutations in patients with Parkinson's disease in southern Spain

Background and purpose:  Mutations in leucine-rich repeat kinase 2 ( LRRK2 ) gene are associated with both familial and idiopathic Parkinson's disease (PD), whereas mutations in PARK2 ( PARKIN ) gene result in early onset recessive PD. Here, the objectives were to determine the frequency of LRRK2 G2019S and R1441G mutations in a PD population from southern Spain; to search for LRRK2 mutations in familial PD cases and to study the effect of PARKIN mutations on clinical features of LRRK2 -associated; PD.
Methods:  We included 187 PD patients (172 idiopathic, 15 familial) and 287 control subjects from southern Spain. LRRK2 and PARKIN mutations were screened, and clinical features of LRRK2 -associated PD were examined.
Results:  Three (1.7%) idiopathic PD patients carried the G2019S, whereas another three (1.7%) had the R1441G. A novel polymorphism D1420N was found in two (13.3%) familial PD patients. One G2019S carrier also had a homozygous PARKIN deletion, who had early onset PD with clinical symptoms similar to those with PARKIN -associated PD. The remaining LRRK2 -asscociated patients had clinical manifestations similar to those with idiopathic PD.
Conclusions:  G2019S and R1441G are common LRRK2 mutations in PD patients in this region. PARKIN mutations override clinical features in LRRK2 -associated PD.     

The G2019S LRRK2 mutation is uncommon amongst Greek patients with sporadic Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder affecting approximately 2% of the population >60 years of age. Although, the etiology of PD is still unknown, the genetic background of the disease has been documented. Recently, a mutation in the LRRK2 gene, G2019S, was associated with 3–41% and 1–2% of familial and sporadic PD, respectively suggesting a pivotal role of LRRK2 in PD. In this report, we examine the association of the G2019S mutation with sporadic late-onset PD, in an independent cohort of Greek patients and controls.     

Molecular biology changes associated with LRRK2 mutations in Parkinson's disease

Parkinson's disease (PD) is characterized by progressive dopaminergic neuronal loss in the substantia nigra. The recent discovery of leucine-rich-repeat kinase 2 gene (LRRK2) mutations in PD is significant because these mutations are the most common cause of autosomal dominant PD. Furthermore, a common recurrent mutation (G2019S) is associated with a significant proportion of nonfamilial PD, and a polymorphic variant (G2385R) has been found to increase the risk in the Asian race. The large LRRK2 protein of 280 kD contains three protein-protein interaction domains and two enzymatic domains, the Ras-related GTPase and the kinase. Mutations in these domains have been described in PD patients. Preliminary evidence suggests that some types of LRRK2 mutations increase the kinase activity, and this is associated with significantly higher apoptotic cell death in dopaminergic cell lines and primary neurons; abolishing the kinase function ameliorates this cellular toxicity. It also appears that its GTPase domain can be activated independently, whereas the kinase activity strictly requires the GTPase activation. Mutations in the LRRK2 have displayed notable pleomorphic pathologies that might indicate an upstream role of LRRK2 in cellular signaling pathways. The identification of physiological substrates (likely to be involved in signaling and apoptotic pathways) of LRRK2 remains an important step in our understanding of the role of LRRK2 in the disease process. Further in vitro and in vivo studies will unravel the role of LRRK2 in cell signaling and its impact on proliferation, differentiation, and survival of neurons.     

Screening for LRRK2 R1441 mutations in a cohort of PSP patients from Germany

Background and purpose:  Mutations in the leucine-rich repeat kinase gene ( LRRK2 ) have been shown to be the most common genetic cause of both familial and sporadic Parkinson's disease. Patients harboring LRRK2 mutations develop late onset PD that in most cases cannot be clinically distinguished from idiopathic PD. Furthermore, LRRK2 mutations have been reported to result in a broad spectrum of neuropathological alterations including progressive supranuclear palsy (PSP)-like Tau pathology.
Methods:  We screened a cohort of 88 clinically confirmed PSP patients for mutations in exon 31.
Results:  We did not find any of the known mutations or any new variants.
Conclusions:  Thus, there is no evidence that mutations in exon 31 of LRRK2 are a major risk factor for PSP. Our study, however, cannot rule out that other genetic variations in LRRK2 may be associated with PSP.     

LRRK2 and Parkinson's disease in Norway

Objectives – Mutations in the LRRK2 gene have been associated with both familial and sporadic late-onset Parkinson's disease. A large number of mutations in this gene have been identified; however, for many of these variants, the pathogenicity and relative frequency are unknown. Herein, we investigate the frequency of a number of recently identified LRRK2 mutations in Norway. Methods – We genotyped eight putatively pathogenic LRRK2 mutations (R793M, R1067Q, I1371V, IVS31+3 A>G, M1869T, R1941H, T2356I and G2385R) in a series of 433 patients with Parkinson's disease and 587 controls from Norway. An intronic polymorphism previously reported to be associated with disease susceptibility was also examined (rs10506151). Results – The Lrrk2 R793M substitution was found in two healthy individuals. No other LRRK2 mutations were identified in the Norwegian population, and furthermore no association was observed between rs10506151 and Parkinson's disease ( P  = 0.41). Conclusions – LRRK2 mutations other than the Lrrk2 G2019S mutation are rare in Norway. Our results indicate that the Lrrk2 R793M substitution is most likely a rare polymorphism.     

家族性帕金森病相关遗传基因LRRK2的差异性研究

目的研究汉族人群家族性帕金森病的LRRK2基因的突变情况,并考察其存在的遗传差异性。方法收集21例家族性帕金森病患者,其中有3例来源于同一家族。采集外周血,提取基因组DNA作为模板,扩增LRRK2基因上的p.K616R、p.R1441G、p.R1441C、p.Y1699C、p.G2019S、p.I2020T及p.G2385R 7种突变位点的目标区域,扩增产物经电泳验证后进行Sanger测序,分析LRRK2基因的7种突变类型在样本中的分布情况。采用123I-IMP SPECT分析来自同一家族的3例帕金森病患者的脑缺血情况。结果 Sanger测序结果显示,p.G2385R突变型有5例(23.8%),p.R1441G突变型有3例(14.3%),p.K616R突变型有2例(4.76%),而其他突变型如p.G2019S、p.R1441C、p.Y1699C及p.I2020T则未检出(0%)。123I-IMP SPECT结果显示,对于来源于同一家族的3例帕金森病患者,患者2d的123I123I-IMP SPECT结果未见异常;患者1h的123I-IMP SPECT结果则显示患者双侧额叶区血流量明显下降;患者2b的123I-IMP SPECT结果则显示患者右侧基底节区血流量明显下降。结论首次在中国人群中发现来自一个家族的3例携带p.R1441G突变基因的帕金森患者,其他基因突变型的分布频率也与以往其他地区和种族的研究结果存在明显差异,证实家族性帕金森病携带的LRRK2基因突变型及突变频率均存在区域和种族的差异性。携带p.R1441G突变基因的帕金森患者与先天性帕金森病特征存在差异,原因尚不明确。     

High prevalence of LRRK2 mutations in familial and sporadic Parkinson's disease in Portugal.

Mutations in the Leucine-Rich Repeat Kinase 2 (LRRK2) gene are the most frequent known cause of Parkinson's disease (PD), but their prevalence varies markedly between populations. Here we studied the frequency and associated phenotype of four recurrent LRRK2 mutations (R1441C, R1441G, R1441H, and G2019S) in familial and sporadic PD from a single referral center in Lisbon, Portugal. Among 138 unrelated PD probands, we identified 9 heterozygous G2019S carriers (6.52%) and 1 heterozygous R1441H carrier (0.72%). The G2019S mutation was present in 4 of the 107 sporadic (3.74%) and in 5 of the 31 familial probands (16.1%). Mutations were not found among 101 Portuguese controls. The G2019S mutation was present on a single haplotype and displayed reduced penetrance. Heterozygous parkin gene mutations were also found in 2 G2019S-positive probands, but their pathogenic role is unclear. The clinical phenotype in patients with LRRK2 mutations was indistinguishable from that of typical PD, including impaired sense of smell. The G2019S mutation is a very common genetic determinant among the Portuguese patients with PD, and the R1441H mutation is also present in this population. These data have important implications for the diagnostic work-up and genetic counseling of patients with this disease in Portugal.     

LRRK2 mutations in a clinic-based cohort of Parkinson's disease

In the last decade, major breakthroughs in the understanding of genetic contributions to Parkinson's disease (PD) have been achieved. Recently, mutations in LRRK2 , encoding dardarin, have been found to be responsible for an autosomal dominant parkinsonism (OMIM 607060). We screened 311 subjects (cases: n  = 202, controls: n  = 109) for the three previously reported LRRK2 mutations. Our investigation revealed a sporadic case of PD with a heterozygous mutation G2019S (c.6055G>A). Here, we present the clinical phenotype of this patient and discuss the implications of genetic testing for the G2019S mutation in patients with sporadic PD.     

LRRK2 is a component of granular alpha-synuclein pathology in the brainstem of Parkinson's disease

Classical Parkinson's disease (PD) is characterized by the appearance of Lewy bodies (LBs) in affected brain regions, showing mostly compact alpha-synuclein deposition, in contrast with punctate or granular deposition, hypothesized to represent early stages of aggregation. Leucine-rich repeat kinase 2 (LRRK2) is the commonest mutated gene in inherited and idiopathic PD. LRRK2 mutation carriers display a diverse neuropathology, including alpha-synuclein and tau inclusions, suggesting an upstream role for LRRK2 in protein aggregation. We studied LRRK2 expression throughout the normal human brain with three different antibodies. We also examined the pattern of LRRK2 expression in relation to alpha-synuclein aggregation and LB formation in the brainstem of sporadic LB disease. Physiological LRRK2 expression was not restricted to regions preferentially affected in PD and LRRK2 often localized to the nuclear envelope in addition to the known cytoplasmic expression. In PD, we were able to consistently detect LRRK2 in the halo of a minority (approximately 10%) of nigral LBs using three different antibodies. Only one antibody detected LRRK2 in the core of approximately 80% of classic LBs. In the lower brainstem, most notably in the dorsal motor nucleus of the vagus, we found previously unrecognized LRRK2 labelling of complex globular lesions, filled with LB-like matter showing a punctate or granular staining for alpha-synuclein. This was often accompanied by strong LRRK2 expression within dystrophic neurites. Our findings confirm widespread physiological LRRK2 expression in the human brain and suggest an association of LRRK2 with possible early-stage alpha-synuclein pathology in the brainstem of PD.     

LRRK2 mutations and risk variants in Japanese patients with Parkinson's disease

Mutations in the leucine‐rich repeat kinase 2 (LRRK2) gene are the most common genetic determinant of Parkinson's disease (PD) in European‐derived populations, but far less is known about LRRK2 mutations and susceptibility alleles in Asians. To address this issue, we sequenced the LRRK2 coding region in 36 patients with familial PD, then genotyped variants of interest in an additional 595 PD cases and 1,641 controls who were all of Japanese ancestry. We also performed a meta‐analysis of studies on G2385R, a polymorphism previously reported to associate with PD. One pathogenic (G2019S) and one putative pathogenic (R1067Q) mutation were each observed in two patients with sporadic PD. The overall mutation frequency among patients was 0.6%. G2385R was highly associated with PD under a dominant model in our dataset (adjusted OR, 1.83; 95% CI, 1.31–2.54; P = 3.3 × 10^?4) and similar results were seen in the meta‐analysis (summary OR assuming fixed effects, 2.55; 95% CI, 2.10–3.10). G2385R represents the first consistently replicated common PD susceptibility variant in a non‐European population and its effect size is substantially greater than that reported for other well‐validated genetic risk factors for the disease. However, LRRK2 mutations appear to be rare among Japanese patients with PD. © 2009 Movement Disorder Society     

LRRK2 mutations are a common cause of Parkinson''s disease in Spain

Pathogenic mutations in the leucine-rich repeat kinase 2 gene (LRRK2; PARK8) have been implicated in autosomal dominant, late-onset parkinsonism. The LRRK2 6055G > A (G2019S) mutation is the most common reported to date, and has been observed in a number of different European populations. So far, only the LRRK2 4321C > G (R1441G) mutation has been identified in the Spanish population. Herein we have assessed the frequency of G2019S in a referral-based series of 225 patients with Parkinson's disease (PD) from the region of Asturias, Northern Spain. The mutant allele was identified in five (2.7%) of the sporadic late-onset patients and was not present in control subjects. All carriers displayed genetic profiles consistent with the same haplotype, as previously reported for Lrrk2 G2019S-positive subjects. None of these patients presented with a family history of parkinsonism at the time of diagnosis. Thus, approximately 5% of sporadic patients with PD from the North of Spain have either Lrrk2 G2019S or R1441G substitutions.     

LRRK2 variation and Parkinson's disease in African Americans

The global impact of LRRK2 mutations is yet to be realized with a lack of studies in specific ethnic groups, including those of Asian and African descent. Herein, we investigated the frequency of common LRRK2 variants by complete exon sequencing in a series of publicly available African American Parkinson's disease patients. Our study identified three novel synonymous exonic variants and 13 known coding variations; however, there did not appear to be any frequent (>5%) pathogenic mutations. Given the ethnic‐specific LRRK2 variation previously identified in PD further studies in under‐represented populations are warranted. © 2010 Movement Disorder Society.     

常染色体显性遗传性帕金森病家系临床特征及LRRK2基因分析

目的 研究常染色体显性遗传家族性帕金森病(PD)患者的临床特征及其LRRK2基因突变.方法 对16例常染色体显性遗传家族史的PD患者LRRK2基因的外显子5、13、31、32、35、37、41、48进行测序检测.利用限制性片段长度多态性(RFLP)分析所发现的新突变c.1432 G＞TAsp478Tyr在240例散发性PD患者及214名健康者中的发生频率.结果 常染色体显性遗传家系PD患者与散发性PD患者比较临床特点以晚发为主,首发症状以静止性震颤(9例,56.25%,t=0.558,P=0.679)和动作迟缓(9例,56.25%,t=0.369,P=0.454)最为常见,其次是肌强直(6例,37.50%,t=1.324,P=0.735)和姿势障碍(5例,31.25%,t=2.369,P=0.956),对左旋多巴治疗反应良好,左旋多巴诱导的异动症少见.LRRK2基因突变检测发现6个突变:c.457 T＞C Leu153Leu、c.1432 G＞T Asp478Tyr、c.5457 T＞C Gly1819Gly、c.7153 G＞A Gly2385Arg、IVS31+28 T＞G、IVS37+162 T＞C.其中,c.1432 G＞T Asp478Tyr是未报道过的新突变.在240例散发性PD患者及214名健康者中均未发现有此突变.未发现与PD相关的LRRK2基因突变Arg1441Cys/Gly/His、Arg1514Gln、Tyr1699Cys、Ile2012Thr、Gly2019Ser和Ile2020Thr.结论 常染色体显性遗传性PD患者临床特征表现为典型的PD临床特征,存在LRRK2基因Asp478Tyr和Gly2385Arg突变.Asp478Tyr是未报道过的新突变.     

LRRK2干扰对MPP+诱导PD细胞模型线粒体功能的影响

目的 探讨富亮氨酸重复激酶2(LRRK2)干扰对1-甲基-4-苯基吡啶离子(MPP+)诱导的帕金森病(PD)细胞模型线粒体功能及CaMKK-β/AMPK通路的影响.方法 采用MPP+诱导传代培养的SH-SY5Y细胞构建PD细胞模型.将造模的SH-SY5Y细胞随机分PD模型组、空载转染组(空载转染PD模型细胞)和siRN...     

Small Molecule Kinase Inhibitors for LRRK2 and Their Application to Parkinson's Disease Models

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Several single gene mutations have been linked to this disease. Mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) indicate LRRK2 as promising therapeutic target for the treatment of PD. LRRK2 mutations were observed in sporadic as well as familial PD patients and have been investigated intensively. LRRK2 is a large and complex protein, with multiple enzymatic and protein-interaction domains, each of which is effected by mutations. The most common mutation in PD patients is G2019S. Several LRRK2 inhibitors have been reported already, although the crystal structure of LRRK2 has not yet been determined. This review provides a summary of known LRRK2 inhibitors and will discuss recent in vitro and in vivo results of these inhibitors.     

A common leucine-rich repeat kinase 2 gene mutation in familial and sporadic Parkinson's disease in Russia

A PARK8 form of Parkinson's disease (PD) is caused by a novel gene, leucine-rich repeat kinase 2 ( LRRK2 ), and a single mutation G2019S was found in a proportion of LRRK2 -associated cases of diverse ethnic origins. We performed the LRRK2 G2019S mutation analysis in 304 Russian patients with PD, including 291 sporadic and 13 autosomal dominant cases. The frequency of the LRRK2 G2019S was 0.7% amongst the sporadic patients (2/291) and 7.7% amongst familial PD (1/13). The mutation was also found in three unaffected relatives and absent in 700 control chromosomes. One patient carrying the LRRK2 G2019S was found earlier to have an additional mutation, a heterozygous duplication of exon 5 of the parkin gene. All patients carrying the LRRK2 G2019S exhibited typical levodopa-responsive parkinsonism, and severe levodopa-induced dyskinesia was observed in the patient carrying the LRRK2 and parkin mutations. There was notable variability in ages of the disease onset in G2019S carriers not explained by APOE genotypes. Two subsets of G2019S-positive patients had different PARK8 haplotypes suggesting that the LRRK2 G2019S in Russian patients had arisen independently on different chromosomes. Identification of common LRRK2 mutations in some PD patients without an overt family history has notable implications for genetic counseling.     

G2019S LRRK2 mutation in familial and sporadic Parkinson's disease in Russia.

Among mutations associated with autosomal dominant and sporadic Parkinson's disease (PD) the G2019S substitution in the leucine-rich repeat kinase 2 (LRRK2) gene is the most frequently identified. To estimate its frequency in Russia, we analyzed 208 patients with PD from the Northwestern region of Russia. Of these, 51 patients were probands from families with PD compatible with autosomal dominant inheritance. The control group represented 161 subjects without neurological disorders settled in the same region. The frequency of the G2019S mutation was greater in familial PD (2 [3.9%] of 51) than in sporadic PD (1 [0.6%] of 157). In addition, this mutation was found in the proband's father, who also had PD, in 1 PD family, and in 1 carrier without signs of PD at age 40 in another PD family. All carriers were heterozygous for the G2019S mutation and reported the Ashkenazi Jewish origin. The mutation was not found in the control group.     

Analysis of 14 LRRK2 mutations in Parkinson's plus syndromes and late-onset Parkinson's disease.

The pleomorphic pathology of postmortem LRRK2-positive patients and the frequent association with late-onset Parkinson's disease (LOPD) symptoms suggest that LRRK2 mutations may play a role in Parkinson's Plus disorders and LOPD. Published studies primarily focus on the common G2019S mutation. Analysis of a spectrum of LRRK2 mutations in Parkinson's Plus disorders has yet to be reported. We investigated 14 leucine-rich repeat kinase 2 (LRRK2) mutations in a cohort of Parkinson's Plus disorders and LOPD. A total of 458 patients with progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal ganglionic degeneration (CBGD), atypical Parkinsonism (AP), and LOPD were screened for 14 mutations that span exons 19 to 41 of the LRRK2 gene. Among the LOPD cases, 1 patient was found to harbor the R1441C mutation. He presented with typical features of PD at age of 58 years old and responded well to levodopa. We did not detect any of the 14 mutations in PSP, MSA, CBGD, and AP patients. We highlight the first case of LRRK2 R1441C mutation in late onset sporadic PD of non-European ancestry. Furthermore, extensive mutational screen found LRRK2 mutations to be rare among patients who presented with PSP, MSA, CBGD, and AP.