Phenotypic commonalities in familial and sporadic Parkinson disease

BACKGROUND: Parkinson disease (PD) is a clinically well-documented neurodegenerative disorder. However, the mechanism or mechanisms of its phenotypic expressions are still unknown. OBJECTIVE: To compare phenotypes by examining demographic and clinical features of patients with familial PD and sporadic PD and with or without a family history of PD. DESIGN: Historical review of patients with sporadic PD in clinic-based samples and individual patients diagnosed with PD from families whose linkage to mutations or loci has been identified. SETTING: Movement disorder clinic in a referral center. PATIENTS: A total of 1277 patients with sporadic PD and 40 patients with familial PD. MAIN OUTCOME MEASURES: Clinical features, including distribution by sex, initial motor symptom, location of initial motor symptom, and frequency of asymmetric motor symptoms. RESULTS: Despite different etiologic backgrounds, both familial and sporadic PD exhibited several interesting commonalities, including a higher incidence in men, tremor as the initial motor symptom (predominantly involving the upper extremities), and asymmetric parkinsonism during disease course. CONCLUSIONS: The increased incidence of parkinsonism in men with familial PD suggests that the sex disparity is more likely the result of a protective effect against development of PD in women than of an increased risk in men that is associated with environmental factors. Phenotypic similarity among familial and sporadic PD indicates that a similar topographic distribution of the nigrostriatal lesion exists in patients with either form of PD regardless of apparent genetic influence.     

Impact of gastric emptying on levodopa pharmacokinetics in Parkinson disease patients

Adjunction of the catechol-O-methyltransferase (COMT) inhibitor entacapone (EN) to levodopa/carbidopa (LD/CD) improves motor symptoms in patients with Parkinson disease (PD) by a prolonged elimination of LD. But it is not known whether EN addition influences gastric emptying and thus LD pharmacokinetics and pharmacodynamics. Objectives were to simultaneously determine plasma LD elimination, gastric emptying, and clinical response after a single intake of the same LD dosage as LD/CD--or as (LD/CD/EN) formulation on 2 consecutive days. In both groups, PD patients with delayed gastric emptying had significant lower LD plasma concentrations. Addition of EN did not influence gastric emptying but significantly improved motor response, which was not different for patients with delayed gastric emptying. However, with and without EN adjunction gastric emptying distinctly contributes to the variability of plasma LD bioavailability. This may impact LD delivery to the brain and thus motor response in PD patients. Therefore, fine tuning of LD application, which considers gastric emptying, becomes more and more essential in advanced PD stages with a reduced striatal neuronal dopamine capacity, which is responsible for maintenance of motor response in early PD patients.     

Analysis of the GIGYF2 gene in familial and sporadic Parkinson disease in the Spanish population

Background and purpose: Linkage analysis in familial Parkinson’s disease (PD) identified a locus in 2q36‐37 (PARK11). Sequencing of GIGYF2 identified several variants only present amongst PD individuals. Methods: We analyzed the presence of disease‐associated GIGYF2 variants in familial and sporadic PD from Spanish origin by sequencing of 147 PD individuals. The entire GIGYF2 coding sequence was analyzed in 122 familial PD individuals and exons 2, 4, 8–11, 14 and 25–26 were sequenced in 25 sporadic PD to identify disease‐associated variants. Results: We found no variants associated with PD and failed to identify any of previously PD‐associated GIGYF2 variants in our sample. We identified four novel missense changes in GIGYF2. p.Met48Ile was found in a PD individual who also was a carrier of two PARKIN mutations. p.Q1244_Q1247del variant was present only in one PD individual but not found in 70 controls. However, its location in the highly polymorphic GIGYF2 glutamine/proline‐rich region does not support a role in PD. Two variants (p.P1238insAGC and p.Q1249del) were present both in PD subjects and in controls. Additionally, the p.L1230_Q1237del variant, which was previously considered as a PD‐associated change, was found in one control. Conclusion: Our findings suggest that GIGYF2 mutations are not a frequent cause of PD in the Spanish population, since we found no clearly segregating variants. We propose further analyses in PD subjects from different populations to define the role of GIGYF2. A clear pathogenic mutation in other gene at 2q36‐37 in the PARK11‐linked PD families would definitively disprove GIGYF2 as the responsible gene.     

Complement allotypes in familial and sporadic alzheimer's disease

Summary To resolve conflicting findings on the association of complement allotypes with Alzheimer's disease (AD) we have studied the C4 phenotypes in 33 sporadic cases and in one family with familial AD. We found no association with complement alleles in familial or sporadic AD, even though a familial case had absence of the C4 null allele (C4BQ0). Our data do not suggest a role for complement genes in the pathogenesis of AD. It also seems that the C4B2 allele cannot be used as a marker for AD as has been suggested by others.     

Movement-related cortical activation in familial Parkinson disease

We sought to determine whether or not first-degree relatives of patients with familial Parkinson disease (FDRs) present impaired movement-related cortical activity. We studied 10 familial Parkinson disease subjects, 10 FDRs, and 10 controls and analyzed event-related mu desynchronization (ERD) and beta synchronization. Forty percent FDRs presented reduced premovement mu ERD latency, suggesting that premovement cortical activation is impaired in FDRs.     

Neuropathology of sporadic Parkinson disease before the appearance of parkinsonism: preclinical Parkinson disease

Parkinson disease (PD) is no longer considered a complex motor disorder characterized by parkinsonism but rather a systemic disease with variegated non-motor deficits and neurological symptoms, including impaired olfaction, sleep disorders, gastrointestinal and urinary abnormalities and cardiovascular dysfunction, in addition to other symptoms and signs such as pain, depression and mood disorders. Many of these alterations appear before or in parallel with motor deficits and then worsen with disease progression. Although there is a close relation between motor symptoms and the presence of Lewy bodies (LBs) and neurites filled with abnormal α-synuclein, other neurological alterations are independent of LBs, thereby indicating that different mechanisms probably converge in the degenerative process. This review presents cardinal observations at very early stages of PD and provides personal experience based on the study of a consecutive series of brains with PD-related pathology and without parkinsonism, mainly cases categorized as stages 2–3 of Braak. Alterations in the substantia nigra, striatum and frontal cortex in pPD are here revised in detail. Early modifications in the substantia nigra at pre-motor stages of PD (preclinical PD: pPD) include abnormal small aggregates of α-synuclein which is phosphorylated, nitrated and oxidized, and which exhibits abnormal solubility and truncation. This occurs in association with a plethora of altered molecular events including increased oxidative stress, altered oxidative stress responses, altered balance of L-ferritin and H-ferritin, reduced expression of neuronal globin α and β chains in neurons with α-synuclein deposits, increased expression of endoplasmic reticulum stress markers, increased p62 and ubiquitin immunoreactivity in relation to α-synuclein deposits, and altered distribution of LC3 and other autophagosome/lysosome markers. In spite of the relatively small decrease in the number of dopaminergic neurons in the substantia nigra, which does not reach thresholds causative of parkinsonism, levels of tyrosine hydroxylase and cannabinoid 1 receptor are reduced, whereas levels of adenosine receptor 2A are increased in the caudate in pPD. Moreover, biochemical alterations are also present in the cerebral cortex (at least in the frontal cortex) in pPD including increased oxidative stress and oxidative damage to proteins α-synuclein, β-synuclein, superoxide dismutase 2, aldolase A, enolase 1, and glyceraldehyde dehydrogenase, among others, indicating post-translational modifications of PD-related proteins, and suggesting altered function of pathways involved in glycolysis and energy metabolism in the cerebral cortex in pPD. Current evidence suggests convergence of several altered metabolic pathways leading to chronic neuronal dysfunction, mainly manifested as sub-optimal energy metabolism, altered synaptic function, oxidative and endoplasmic reticulum stress damage and corresponding altered responses, among others. By understanding that these alterations occur at very early stages of PD and that neuronal fatigue and exhaustion may precede, for years, cell death and neuronal loss, we may direct therapeutic strategies towards the prevention and delay of disease progression starting at pre-parkinsonian stages of PD.     

Delayed gastric emptying in Parkinson's disease

Gastrointestinal symptoms are evident in all stages of Parkinson's disease (PD). Most of the gastrointestinal abnormalities associated with PD are attributable to impaired motility. At the level of the stomach, this results in delayed gastric emptying. The etiology of delayed gastric emptying in PD is probably multifactorial but is at least partly related to Lewy pathology in the enteric nervous system and discrete brainstem nuclei. Delayed gastric emptying occurs in both early and advanced PD but is underdetected in routine clinical practice. Recognition of delayed gastric emptying is important because it can cause an array of upper gastrointestinal symptoms, but additionally it has important implications for the absorption and action of levodopa. Delayed gastric emptying contributes significantly to response fluctuations seen in people on long‐term l ‐dopa therapy. Neurohormonal aspects of the brain‐gut axis are pertinent to discussions regarding the pathophysiology of delayed gastric emptying in PD and are also hypothesized to contribute to the pathogenesis of PD itself. Ghrelin is a gastric‐derived hormone with potential as a therapeutic agent for delayed gastric emptying and also as a novel neuroprotective agent in PD. Recent findings relating to ghrelin in the context of PD and gastric emptying are considered. This article highlights the pathological abnormalities that may account for delayed gastric emptying in PD. It also considers the wider relevance of abnormal gastric pathology to our current understanding of the etiology of PD. © 2013 International Parkinson and Movement Disorder Society     

Molecular findings in familial Parkinson disease in Spain

BACKGROUND: Several genetic errors in alpha-synuclein (Park1) and ubiquitin carboxyl-terminal-hydrolase L1(Park5) genes cause autosomal dominant familial Parkinson disease. Mutations in the parkin gene (Park2) are the major cause of autosomal recessive Parkinson disease. OBJECTIVE: To analyze the clinical and molecular data of 19 Spanish kindreds (13 with recessive, 4 with dominant, and 2 with uncertain inheritance) who have familial Parkinson disease. METHODS: We searched for the previously described mutations in Park1 and Park5 genes and for new or described mutations in Park2. We used single-strand conformation polymorphism, direct sequencing, and restriction digestion of polymerase chain reaction (PCR)-amplified genomic DNA for this study. RESULTS: None of these families have either Park1 or Park5 mutations. We found 5 different mutations in Park2 gene in 5 of the families with recessive inheritance. To our knowledge, 2 of these mutations, V56E and C212Y, have not been previously reported. The other mutations found (deletion of exons 3 and 5 and 225delA) have been described in other ethnic groups. Heterozygous carriers of a single Park2 mutation either were asymptomatic or developed clinical symptoms in late adulthood or after brief exposure to haloperidol therapy. CONCLUSIONS: Mutations in Park2 gene account for 38% of the families with recessive parkinsonism in Spain. We found 2 cases of simple heterozygous Park2 mutation carriers that developed clinical symptoms, either in late adulthood or after brief exposure to parkinsonizing agents. Thus, hereditary Parkinson disease has more variable clinical phenotype and molecular defects than previously thought since heterozygous mutations could be a risk factor for parkinsonism.     

Lack of familial aggregation of Parkinson disease and Alzheimer disease

OBJECTIVE: To investigate the risk of Alzheimer disease (AD) in first-degree relatives of patients with Parkinson disease (PD) compared with first-degree relatives of controls. DESIGN: Case-control study, family history method, and reconstructed cohort approach. METHODS: Probands with PD without dementia and control probands, matched by age strata, sex, and ethnicity, were examined in person and enrolled without knowledge of family history of PD and other neurological disorders. Disease status in first-degree relatives of probands with PD and control probands was ascertained through a structured family history interview administered to the proband and a second informant (self-report or another informant). Cox proportional hazards models with double-censoring techniques for missing information on age of onset of AD were used to analyze the risk of AD in first-degree relatives of patients with PD compared with first-degree relatives of controls. RESULTS: Four hundred eighty-seven probands with PD and 409 control probands provided family history information on 4819 first-degree relatives older than 30 years (2534 relatives of probands with PD and 2285 relatives of control probands). One hundred thirteen first-degree relatives (2.3%; 61 relatives [2.4%] of patients with PD and 52 relatives [2.3%] of controls) were diagnosed with AD. The risk of AD was not increased in relatives of patients with PD compared with relatives of controls (hazard ratio, 1.1; 95% confidence interval, 0.7-1.6; P =.65). Similarly, no significantly increased risk of AD was observed when comparing relatives of patients with early-onset (< or =50 years) and late-onset (>50 years) PD with relatives of controls. CONCLUSION: The lack of familial aggregation of PD and AD does not support the hypothesis of major shared genetic contributions to the etiology of the 2 most common neurodegenerative disorders.     

Predictors of gastric emptying in Parkinson''s disease

Predictors of gastric emptying (GE) in patients with idiopathic Parkinson's disease (PD) of a solid and liquid meal are not well defined. For measurement of GE 80 patients with PD were randomly assigned to receive either a solid meal (250 kcal) containing 13C-octanoate (n = 40) or a liquid meal (315 kcal) with 13C-acetate (n = 40). All patient groups were off medication affecting motility and were matched for age, gender, body mass index, disease duration and severity, using Unified Parkinson's Disease Rating Scale (UPDRS). Gastric emptying was compared with a healthy control group (n = 40). Multiple regression analysis was used to determine predictors of gastric emptying. Exactly 88% and 38% of PD patients had delayed GE of solids and liquids respectively. Solid and liquid emptying was similar in women and men. There were no differences in GE in PD patients < 65 years of age when compared with patients > or = 65 years. Multiple regression analysis showed that motor handicaps such as rigour and action tremor are independent predictors of solid GE (r = 0.68, P < 0.001). The severity of motor impairment, but not any other neurological symptom, as assessed by UPDRS is associated with gastroparesis in PD and solid emptying is more likely to be delayed.     

Levels of alpha-synuclein mRNA in sporadic Parkinson disease patients.

Lewy bodies, the pathological hallmark of Parkinson's disease (PD), consist largely of alpha-synuclein, a 14.5-kDa presynaptic neuronal protein implicated in familial PD. An increased copy number and elevated expression of wild-type alpha-synuclein (SNCA) has been shown to cause early-onset familial PD. However, it is not clear whether increased alpha-synuclein expression also plays a role in the pathogenesis of sporadic disease. In the current study, we analyzed the levels of SNCA-mRNA in affected brains of sporadic PD patients. We compared the levels of steady state SNCA-mRNA in 7 sporadic PD brain samples and 7 normal controls using real-time polymerase chain reaction of RNA extracted from mid-brain tissue, including the substantia nigra. Despite that there is neuronal loss in the substantia nigra of PD brains, overall the SNCA-mRNA levels were increased in PD brains an average of nearly fourfold over normal control mid-brain, although there was much greater variability in samples from PD patients compared to controls. Frontal cortex samples from selected individuals were also analyzed. SNCA-mRNA levels were not significantly changed in PD frontal cortex compared to controls. These results suggest that elevated expression levels of SNCA-mRNA are found in the affected regions of PD brain and support the hypothesis that increases in alpha-synuclein expression is associated, among other factors, with the development of sporadic PD.     

Clinical characteristics of familial and sporadic Creutzfeldt-Jakob disease in Finland

The clinical features of 44 Finnish patients with Creutzfeldt-Jakob disease (CJD) were analyzed with special emphasis on the differences between the sporadic and familial forms. The 32 sporadic patients comprised all neuropathologically verified cases of CJD in 1974–89 in Finland. The 12 familial patients were members of the same pedigree where CJD has been linked with a mutation at codon 178 of the PRNP gene. The median age at the onset of the disease was 62.5 years and median duration 4.5 months in sporadic patients, and 49 years and 20.5 months in familial CJD, respectively. 90 percent of both sporadic and familial patients had myoclonus. Typical periodic EEG change was seen in 72% of sporadic patients, whereas the familial patients showed only a progressive slowing of EEG.     

Parkin mutations in familial and sporadic Parkinson's disease among Indians

We observed a mutation frequency of 8.5% in Parkin gene among Indian PD patients based on sequencing and gene dosage analysis of its exons. We identified nine point mutations of which seven are novel and hitherto unreported. These mutations accounted for 14.3% familial PD, 6.9% young onset and 5.9% late onset sporadic PD. Of the 20 PD patients with mutations only two had homozygous mutations and one was a compound heterozygote. Homozygous exonic deletions were absent but heterozygous exon rearrangements were observed in 9.2% of patients (19% familial PD and 4.5% young onset sporadic PD).     

Presenilin-1 protein expression in familial and sporadic Alzheimer's disease

Mutations of the presenilin PS1 and PS2 genes are closely linked to aggressive forms of early-onset (<60 years) familial Alzheimer's disease. A highly specific monoclonal antibody was developed to identify and characterize the native PS1 protein. Western blot analyses revealed a predominant 32-kd immunoreactive polypeptide in a variety of samples, including PC12 cells transfected with human PS1 complementary DNA, brain biopsy specimens from demented patients, and postmortem samples of frontal neocortex from early-onset familial Alzheimer's disease cases (PS1 and PS2), lateonset sporadic Alzheimer's disease cases, and cases of other degenerative disorders. This truncated polypeptide contains the N-terminus of PS1 and appeared unchaged across cases. In 2 early-onset cases linked to missense mutations in the PS1 gene, a PS1 immunoreactive protein (～49 kd) accumulated in the frontal cortex. This protein was similar in size to full-length PS1 protein present in transfected cells overexpressing PS1 complementary DNA, and in lymphocytes from an affected individual with a deletion of exon 9 of the PS1 gene, suggesting that mutations of the PS1 gene perturb the endoproteolytic processing of the protein. Immunohistochemical studies of control brains revealed that PS1 is expressed primarily in neurons, with the protein localized in the soma and dendritic processes. In contrast, PS1 showed striking localization to the neuropathology in early-onset familial Alzheimer's disease and sporadic Alzheimer's disease cases. PS1 immunoreactivity was present in the neuritic component of senile plaques as well as in neurofibrillary tangles. Localization of PS1 immunoreactivity in familial and sporadic Alzheimer's disease suggests that genetically heterogeneous forms of the disease share a common pathophysiology involving PS1 protein.     

Brain metabolic differences between sporadic and familial Alzheimer's disease

This FDG-PET study with SPM99 compared 46 patients with sporadic Alzheimer disease (SAD) to 40 patients with familial AD (FAD) and to 35 matched controls. AD groups had equivalent metabolic (METglu) reductions in several cortical and limbic areas with respect to the controls. Patients with FAD showed decreased METglu in the posterior cingulate, parahippocampal, and occipital cortex as compared to the patients with SAD (p < 0.001). Genetic factors lead to phenotypic differences in AD.