Raquel Duran

A Multicenter Study of Glucocerebrosidase Mutations in Dementia With Lewy Bodies

IMPORTANCE While mutations in glucocerebrosidase (GBA1) are associated with an increased risk for Parkinson disease (PD), it is important to establish whether such mutations are also a common risk factor for other Lewy body disorders. OBJECTIVE To establish whether GBA1 mutations are a risk factor for dementia with Lewy bodies (DLB). DESIGN We compared genotype data on patients and controls from 11 centers. Data concerning demographics, age at onset, disease duration, and clinical and pathological features were collected when available. We conducted pooled analyses using logistic regression to investigate GBA1 mutation carrier status as predicting DLB or PD with dementia status, using common control subjects as a reference group. Random-effects meta-analyses were conducted to account for additional heterogeneity. SETTING Eleven centers from sites around the world performing genotyping. PARTICIPANTS Seven hundred twenty-one cases met diagnostic criteria for DLB and 151 had PD with dementia. We compared these cases with 1962 controls from the same centers matched for age, sex, and ethnicity. MAIN OUTCOME MEASURES Frequency of GBA1 mutations in cases and controls. RESULTS We found a significant association between GBA1 mutation carrier status and DLB, with an odds ratio of 8.28 (95% CI, 4.78-14.88). The odds ratio for PD with dementia was 6.48 (95% CI, 2.53-15.37). The mean age at diagnosis of DLB was earlier in GBA1 mutation carriers than in noncarriers (63.5 vs 68.9 years; P < .001), with higher disease severity scores. CONCLUSIONS AND RELEVANCE Mutations in GBA1 are a significant risk factor for DLB. GBA1 mutations likely play an even larger role in the genetic etiology of DLB than in PD, providing insight into the role of glucocerebrosidase in Lewy body disease.

Glucocerebrosidase mutations influence the natural history of Parkinson's disease in a community-based incident cohort

Carriers of mutations in the glucocerebrosidase gene (GBA) are at increased risk of developing Parkinsons disease. The frequency of GBA mutations in unselected Parkinsons disease populations has not been established. Furthermore, no previous studies have investigated the influence of GBA mutations on the natural history of Parkinsons disease using prospective follow-up. We studied DNA from 262 cases who had been recruited at diagnosis into one of two independent community-based incidence studies of Parkinsons disease. In 121 cases, longitudinal data regarding progression of motor disability and cognitive function were derived from follow-up assessments conducted every 18 months for a median of 71 months. Sequencing of the GBA was performed after two-stage polymerase chain reaction amplification. The carrier frequency of genetic variants in GBA was determined. Baseline demographic and clinical variables were compared between cases who were either GBA mutation carriers, polymorphism carriers or wild-type homozygotes. Cox regression analysis was used to model progression to major motor (Hoehn and Yahr stage 3), and cognitive (dementia) end-points in cases followed longitudinally. We show that in a representative, unselected UK Parkinsons disease population, GBA mutations are present at a frequency of 3.5%. This is higher than the prevalence of other genetic mutations currently associated with Parkinsons disease and indicates that GBA mutations make an important contribution to Parkinsons disease encountered in the community setting. Baseline clinical characteristics did not differ significantly between cases with and without GBA sequence variants. However, the hazard ratio for progression both to dementia (5.7, P = 0.003) and Hoehn and Yahr stage 3 (4.2, P = 0.003) were significantly greater in GBA mutation carriers. We also show that carriers of polymorphisms in GBA which are not generally considered to increase Parkinsons disease risk are at significantly increased risk of progression to Hoehn and Yahr stage 3 (3.2, P = 0.004). Our results indicate that genetic variation in GBA has an important impact on the natural history of Parkinsons disease. To our knowledge, this is the first time a genetic locus has been shown to influence motor progression in Parkinsons disease. If confirmed in further studies, this may indicate that GBA mutation status could be used as a prognostic marker in Parkinsons disease. Elucidation of the molecular mechanisms that underlie this effect will further our understanding of the pathogenesis of the disease and may in turn suggest novel therapeutic strategies.

The Glucocerobrosidase E326K Variant Predisposes to Parkinson’s Disease, But Does Not Cause Gaucher’s Disease

Heterozygous loss‐of‐function mutations in the acid beta‐glucocerebrosidase (GBA1) gene, responsible for the recessive lysosomal storage disorder, Gauchers disease (GD), are the strongest known risk factor for Parkinsons disease (PD). Our aim was to assess the contribution of GBA1 mutations in a series of early‐onset PD.

Hyposmia and cognitive impairment in Gaucher disease patients and carriers

The objective of this study was to assess a cohort of Gaucher disease patients and their heterozygous carrier relatives for potential clinical signs of early neurodegeneration. Gaucher disease patients (n = 30), heterozygous glucocerebrosidase mutation carriers (n = 30), and mutation‐negative controls matched by age, sex, and ethnicity (n = 30) were recruited. Assessment was done for olfactory function (University of Pennsylvania Smell Identification Test), cognitive function (Mini‐Mental State Examination, Montreal Cognitive Assessment), rapid eye movement sleep disorder, autonomic symptoms, and parkinsonian motor signs (Unified Parkinsons Disease Rating Scale part III, Purdue pegboard). Olfactory function scores were significantly lower in Gaucher disease patients (P = .010) and heterozygous carriers (P < .001) than in controls. Cognitive assessment scores were significantly lower in Gaucher disease patients (P = .002) and carriers (P = .002) than in controls. Unified Parkinsons Disease Rating Scale motor subscale scores were significantly higher in Gaucher disease patients (P < .001) and heterozygotes (P = .0010) than in controls. There was no difference in scores for symptoms of rapid eye movement sleep disorder or autonomic dysfunction. Impairment of olfaction, cognition, and parkinsonian motor signs occurs more frequently in Gaucher disease patients and carriers than in controls, which may indicate the early stages of neurodegeneration.

Plasma α-synuclein in patients with Parkinson's disease with and without treatment

Alpha‐synuclein (α‐syn) is an intracellular protein with a high tendency to aggregation. It is the major component of Lewy bodies and may play a key role in the pathogenesis of Parkinsons disease (PD). α‐Syn is also released by neurons and can be detected in biological fluids, such as plasma. The purpose of this study was to determine whether plasma α‐syn concentrations are elevated in newly diagnosed PD patients before treatment (nontreated PD group, ntPD; n = 53) and to compare them with concentrations in PD patients with at least 1 year of specific treatment (tPD; n = 42) and in healthy controls (n = 60). Plasma α‐syn concentrations in the ntPD and tPD groups were similar and significantly higher than in healthy controls. In conclusion, α‐syn was elevated early in the development of PD and specific PD treatment did not change plasma α‐syn levels.

A clinical and family history study of Parkinson's disease in heterozygous glucocerebrosidase mutation carriers

Type I Gaucher disease (GD), the most common lysosomal storage disorder, is caused by recessive glucocerebrosidase mutations.1 Both patients with Type I GD and heterozygous glucocerebrosidase mutation carriers have increased Parkinsons disease (PD) risk.1 Non-motor symptoms (NMS) are more frequent in PD with heterozygous glucocerebrosidase mutations (PD-GBA).2 We used the non-motor symptoms scale (NMSS) and Parkinsons disease questionairre (PDQ-39) to quantify NMS in PD-GBA.3 The age related PD risk in heterozygous glucocerebrosidase carriers has been reported in familial PD.4 Here, we calculate PD risk in obligate carrier relatives (parents) of Type I GD patients. ### Patients and methods PD-GBA patients were identified by Sanger sequencing of the glucocerebrosidase gene in 220 sporadic PD (PD-S) patients. The G2019S mutation in LRRK2 had previously been excluded. A control group of glucocerebrosidase mutation negative PD-S were selected from the same cohort. Each participant had the following administered: 40 item smell identification test (SIT), Montreal Cognitive assessment (MoCA), Parts I–IV of Unified Parkinsons Disease Rating Scale (UPDRS), NMSS, PDQ-39 and Rapid Eye Movement (REM) Sleep Behaviour Disorder Questionnaire (RBDQ). Statistical analysis was performed using SPSS (version 17). The proportion of participants with a MoCA score 6/10 (signifying possible REM sleep behaviour disorder) was compared using the χ2 test.3 In parallel, family history data were obtained from 83 Type I GD patients, detailing age of onset of PD in their parents …

Plasma lipid peroxidation in sporadic Parkinson's disease. Role of the l-dopa

Oxidative stress plays an important role in the pathogenesis of neurodegenerative diseases, such as Parkinsons disease (PD). There are several methods to measure oxidative stress, being lipid peroxidation (LPO) one of the most frequently used. Endogenous plasma LPO was determined by a spectrofluorimetric method in fifty two patients with sporadic PD and in forty controls. To know the maximum capacity of lipids to peroxidate, LPO was also measured after co-incubation with Fe2+/H2O2 (exogenous LPO). All PD patients were taken L-dopa and the effect of this treatment on LPO levels was additionally studied. Urine catecholamines and their main metabolites were also analyzed, and their possible correlation to LPO statistically studied. Endogenous plasma LPO levels were 33% higher in PD group than in control group (P<0.001). Exogenous plasma or oxidizability was also higher in PD patients compared to controls (20%, P<0.05). The intake of L-dopa was negatively dose-related to endogenous and exogenous plasma LPO. In conclusion, plasma of PD patients has elevated levels of LPO and also is more prone to peroxidation than that in the control group. The results also suggest an antioxidant effect of L-dopa.

Review: Brain Aminopeptidases and Hypertension

The brain aminopeptidases that participate in the enzymatic cascade of the renin-angiotensin system play a major role in blood pressure (BP) control, and their study offers new perspectives for the understanding of central BP control and the treatment of hypertension. In this system, angiotensin II is converted to angiotensin III (Ang III) by glutamyl aminopeptidase (GluAP) and Ang III is further metabolised to angiotensin IV by alanyl aminopeptidase or arginine-aminopeptidase. It is now clear that Ang III is the key active form of the central angiotensins, exerting tonic stimulatory control over BP Therefore, the development of GluAP inhibitors as potential antihypertensive agents offers new perspectives for therapy. Brain aspartyl JR aminopeptidase, which converts angiotensin I to angiotensin 2-10, is also a possible target for antihypertensive therapy because of its potential role in BP control. Finally, since changes in BP levels, that paralleled changes in brain and plasma aminopeptidase activities, were observed after unilateral lesions of the nigrostriatal system, brain asymmetry, aminopeptidase activities and BP control appear to be related, resulting their interplay in an asymmetrical neuroendocrine response that differentially affect BP control.The study of this interaction may contribute to our understanding of how the brain controls BP

Genotype and phenotype in Parkinson's disease: lessons in heterogeneity from deep brain stimulation.

Variation in the genetic risk(s) of developing Parkinsons disease (PD) undoubtedly contributes to the subsequent phenotypic heterogeneity. Although patients with PD who undergo deep brain stimulation (DBS) are a skewed population, they represent a valuable resource for exploring the relationships between heterogeneous phenotypes and PD genetics. In this series, 94 patients who underwent DBS were screened for mutations in the most common genes associated with PD. The consequent genetic subgroups of patients were compared with respect to phenotype, levodopa (l‐dopa), and DBS responsiveness. An unprecedented number (29%) of patients tested positive for at least 1 of the currently known PD genes. Patients with Parkin mutations presented at the youngest age but had many years of disease before needing DBS, whereas glucocerebrosidase (GBA) mutation carriers reached the threshold of needing DBS earlier, and developed earlier cognitive impairment after DBS. DBS cohorts include large numbers of gene positive PD patients and can be clinically instructive in the exploration of genotype‐phenotype relationships.

Oxidative stress and plasma aminopeptidase activity in Huntington's disease.

Huntington’s disease (HD) is a genetic neurodegenerative disorder. Oxidative stress, mitochondrial dysfunction, and protein metabolism impairment have been implicated in its pathogenesis. However, the contribution of these phenomena to HD onset or progression is not well known, and they have been less studied in peripheral blood. We analyzed plasma lipid peroxide (LPO) and lactate (LAC) concentrations as indicators of oxidative stress and mitochondrial dysfunction in symptomatic HD patients (sHD) and asymptomatic HD gene carriers (aHD). We also measured the plasma activity of aminopeptidases (APs), an important group of proteolytic enzymes. LPO and LAC concentrations were significantly elevated in sHD patients but not in aHD carriers. Aspartate and glutamate AP activities were significantly reduced in sHD patients and aHD carriers. These findings demonstrate that sHD patients are under oxidative stress, which may favor progression of the disease. Plasma AP activity was decreased before the appearance of HD symptoms and oxidative stress and may be related to protein metabolism impairment. These results indicate that therapy directed to improve oxidative stress and normalize AP activity may be useful in the treatment of HD. They also suggest that decreased plasma AP activity in aHD carriers may predict the future onset of HD symptoms.