Cancer in Parkinson’s disease

INTRODUCTIONWe examined the prevalence of cancer in patients with Parkinson’s disease (PD) and controls evaluated at the Mayo Clinic in Jacksonville, Florida, between 2003 and 2014.METHODSWe retrospectively collected information regarding cancer diagnoses and diagnosis of PD from 971 unrelated PD patients and 478 controls, and all were white. For PD patients, we examined cancers diagnosed before and after PD diagnosis separately in addition to considering all cancer diagnoses.RESULTSTwenty different cancers were identified. In PD patients, the most common types of cancer were skin cancer (17.3% overall; 10.6% before PD), followed by nonmelanoma skin cancer (16.0% overall; 9.7% before PD), prostate cancer in men (12.8% overall; 9.2% before PD), breast cancer in women (10.6% overall; 6.3% before PD), and melanoma (2.4% overall; 1.1% before PD). Compared to controls, a significantly lower frequency of nonmelanoma skin cancer (odds ratio [OR]: 0.62, P = 0.0024) and any skin cancer (OR: 0.57, P = 0.0002) was observed in PD patients. These differences were greater when considering only cases with cancers that occurred before PD diagnosis (OR: 0.49, P < 0.0001; OR: 0.45, P < 0.0001, respectively), and there was a lower frequency of melanoma and any cancer preceding PD diagnosis compared to controls (OR: 0.31, P = 0.003; OR: 0.36, P < 0.0001). There was no evidence of a frequency difference for any other cancer.CONCLUSIONSPD patients had a lower frequency of skin cancers or any cancer prior to PD diagnosis compared to controls, suggesting that cancer may have a protective effect on PD risk.     

Nigral degeneration and striatal dopaminergic dysfunction in idiopathic and Parkin-linked Parkinson's disease.

We have used MR segmented inversion recovery ratio imaging (SIRRIM) of the substantia nigra pars compacta to detect and correlate nigral signal change in idiopathic Parkinson's disease (PD) and parkin patients with striatal (18)F-dopa uptake. Nine PD patients, nine parkin patients, and eight control subjects were studied with a combination of MR inversion recovery sequences sensitive to nigral cell loss. Blinded independent observer rating and quantified nigral signal analysis were performed on all subjects. Striatal regions of interest were defined on T(1)-weighted MRI co-registered to (18)F-dopa positron emission tomography. On blinded observer rating of the SIRRIM dorsal and ventral nigral images, 25% (2/8) of control subjects, 44% (4/9) of PD patients, and 67% (6/9) of parkin patients were classified as abnormal. Quantified total nigral signal intensities were reduced to a greater extent in the parkin compared to PD patients. There was a greater predilection for signal reduction in the ventral nigral slice of the PD compared to the parkin patient group, who showed a more uniform involvement. All PD and parkin patients were discriminated from controls on the basis of caudate and putamen (18)F-dopa Ki reductions. Our results suggest that MR segmented inversion recovery ratio imaging shows poor sensitivity for discriminating parkin and idiopathic PD patients from normal controls. Where nigral signal abnormalities were seen, parkin patients manifested generalized nigral cell loss with widespread striatal dopamine terminal dysfunction compared with the lateral nigral targeting seen in PD and selective loss of putamen (18)F-dopa uptake.     

It's a double knock-out! The quaking mouse is a spontaneous deletion of parkin and parkin co-regulated gene (PACRG).

Mutations in the parkin gene (PRKN) are the commonest cause of juvenile and early-onset parkinsonism. However, the pathogenic mechanism by which loss of parkin protein results in degeneration of dopaminergic neurons remains elusive. Animal models provide a useful tool for the study of development and disease, and the recent production of transgenic fly and mouse parkin deficient models allows investigation of the molecular role of parkin in dopamine regulation and nigrostriatal function. We have identified the mouse mutant Quaking as a spontaneously occurring PRKN knockout. The quaking mutation is a deletion of approximately 1.17 Mb of mouse chromosome 17, resulting in the deletion of the entire promoter and first five coding exons of PRKN In addition, the recently described Parkin Co-Regulated Gene (PACRG) is completely deleted. Homozygous Quaking mice show a complete loss of PRKN and PACRG mRNA and protein. These mice will constitute a useful additional model for studies of the molecular role of parkin and PACRG in neurodegeneration.     

Exon Deletions of Parkin Gene in Patients with Parkinson Disease

Mutations in the parkin gene have recently been identified in familial and isolated patients with early-onset Parkinson disease (PD) and that subregions between exon 2 and 4 of the parkin gene are hot spots of deletive mutations. To study the distribution of deletions in the parkin gene among variant subset patients with PD in China, and to explore the role of parkin gene in the pathogenesis of PD, 63 patients were divided into early onset and later onset groups. Exons 1-12 were amplified by PCR, templated by the genomic DNA of patients, and then the deletion distribution detected by agarose electrophoresis. Four patients were found to be carrier of exon deletions in 63 patients with PD. The location of the deletion was on exon 2 ( 1 case), exon 3 (2 cases) and exon 4 (1 case). All patients were belong to the group of early onset PD. The results showed that parkin gene deletion on exon 2, exon 3 and exon 4 found in Chinese population contributes partly to early onset PD.     

Involvement of spinal motor neurons in parkin‐positive autosomal recessive juvenile parkinsonism

We intensively examined the spinal cord of an autosomal recessive juvenile parkinsonism (ARJP) female patient with a homozygous exon 3 deletion in the parkin gene, anticipating a possible involvement of anterior horn neurons. Although the clinical features of the patient were consistent with parkinsonism as a result of parkin mutation, her tendon reflex was abolished in the lower limbs. This feature was in contrast with hyperreflexia, usually found in previous reports of ARJP. Histologically, on the level of the cervical, thoracic, and sacral spinal cord, anterior horn neurons were well preserved and normal. However, the lumbar spinal cord exhibited many swellings of proximal axons (spheroids) and degenerative changes in the somata of the large anterior horn neurons such as central chromatolysis, cystatin C‐negative small eosinophilic inclusions, and eosinophilic Lewy body‐like inclusions. Ultrastructurally, accumulations of neurofilaments and abnormal structures, such as inclusion bodies similar to skein‐like inclusions and disorganized rough endoplasmic reticulum, were observed in the somata and neuronal processes. Lewy body‐like inclusions in this study were positively immunostained for both α‐synuclein and ubiquitin that closely resemble Lewy bodies, but are different from Lewy body‐like inclusions negatively immunostained for α‐synuclein in amyotrophic lateral sclerosis. These findings suggest that eosinophilic inclusions that closely resemble Lewy bodies may be formed in the spinal motor neurons of ARJP patients with parkin mutations and the motor neurons of these patients may be vulnerable to neurodegeneration.     

Genetic testing in Parkinson's disease.

Parkinson's disease (PD) is a common neurodegenerative disorder of adulthood characterized clinically by rigidity, bradykinesia, resting tremor, and postural instability. The annual incidence of PD ranges between 16 and 19 individuals per 100,000 (Twelves et al., Mov Disord 2003;18:19-31). Historically, PD has been commonly viewed as an idiopathic or environmentally triggered condition. However, as is true with most common conditions, there have been several families reported with PD who demonstrate a classic Mendelian pattern of inheritance. To date, nine genetic loci have been reported and four pathogenic genes have been identified: alpha-synuclein, parkin, DJ1, and PINK1. Families with alterations in these genes or linked sites demonstrate either recessive or dominant inheritance patterns and may have typical and/or atypical symptoms, with an age of onset extending from the second to the sixth decade. Commercial tests for parkin and alpha-synuclein mutations are now available. We predict that physicians, particularly neurologists, increasingly will be approached for information and referrals regarding genetic testing. To assist patients and their families, physicians will not only need to know when such testing is likely to yield a meaningful result but also be aware of the possible social and emotional consequences of testing. The following is a review of what is currently known about the genetics of PD within this context. We discuss what is known about genetic testing for Huntington's disease, a well-described model for genetic testing in a neurodegenerative disorder. We explore the utility, appropriateness, and possible implications of genetic testing for diagnostic and presymptomatic purposes.     

Does parkin play a role in the peripheral nervous system? A family report

Two genes were identified for autosomal recessive forms of early onset Parkinson's disease: parkin and DJ-1. We describe 2 siblings with EOPD due to parkin mutations and peripheral neuropathy, which presented as neuropathy with liability to pressure palsies (HNPP) in the index case. RT-PCR experiments revealed that the parkin gene is expressed in sural nerves from both controls and patient with parkin-related disease. Our findings support the view that parkin may play a role in the peripheral nervous system.     

应用变性高效液相色谱技术检测parkin基因突变

目的应用变性高效液相色谱技术(denaturing high performance liquid chromatography,DHPLC)检测早发性帕金森综合征(early-onset parkinsonism,EOP)致病基因parkin突变。方法散发EOP患者82例,提取外周血细胞DNA,通过PCR扩增parkin基因的12个外显子,应用DHPLC进行变异筛查,峰形异常者进行DNA测序以明确序列变异的种类和位置。结果以100名健康者为正常对照,在82例EOP患者中检测出3种突变,均为点突变,内含子区突变包括IVS1-39G→T和IVS9 18C→T;编码区突变为T1422C,导致所编码的441位氨基酸由半胱氨酸变为精氨酸(Cys441Arg)。结论在散发EOP患者中发现3个杂合型点突变,探讨应用DHPLC在EOP患者中开展parkin基因诊断的可行性。     

早发性帕金森病parkin基因第1～6外显子缺失突变的初步研究

目的 探讨中国人早发性帕金森病（ｐｒａｅｃｏｘ Ｐａｒｋｉｎｓｏｎ ｄｉｓｅａｓｅ,ＰＰＤ）中ｐａｒｋｉｎ基因第１～６外显子是否存在突变,及其与该病临床特点的关系。方法 用ＰＰＤ患者外周血液提取ＤＮＡ,通过ＰＣＲ扩增,琼脂糖凝胶电泳鉴定ｐａｒｋｉｎ基因外显子缺失突变,并结合临床资料分析。结果 ２１中层得中发现有２例第１外显子缺失,２例第４外显子缺失,１例第６外显子缺失;发生基因缺失突变的病例年龄为