Prevalence Of Parkinson's Disease Research Articles

Gender differences in Parkinson's disease: A clinical perspective.

Available data indicate that there are gender differences in many features of Parkinson's disease (PD). Precise identification of the gender differences is important to tailor treatment, predict outcomes, and meet other individual and social needs in women and men with PD. The aim of this study was to review the available clinical data on gender differences in PD. Original articles and meta-analyses published between 1990 and 2016 systematically exploring gender differences in PD were reviewed. There is slight male preponderance in incidence and prevalence of PD. PD starts earlier in men. Women tend to be more prone to develop tremor-dominant PD but are less rigid than men. Motor improvement after deep brain stimulation is equal in both sexes, but women tend to show better improvement in activities of daily living. Furthermore, women with PD show better results on tests for general cognitive abilities, outperform men in verbal cognitive tasks, show more pain symptoms, and score higher on depression scales. It seems, however, that the differences in cognition, mood, and pain perception are not disease specific as similar gender differences can be found in healthy subjects and in other neurological conditions. Despite PD being the most frequently studied movement disorder, studies investigating gender differences in PD are still scarce with most of the studies being cross-sectional. Good-quality, prospective, longitudinal studies analyzing gender differences in PD and comparing them to matched healthy controls are needed in order to properly address the issues of gender differences in PD.

Association between Parkinson's disease and diabetes: Data from NEDICES study.

Despite growing evidence showing an association between Parkinson's disease (PD) and diabetes, epidemiological studies have shown conflicting results. To evaluate the association between PD and diabetes and the impact of diabetes duration in this association in an elderly (≥65years) Spanish population. Data for this cross-sectional population-based analysis were obtained from NEDICES study. Subjects were identified from census list. Diagnosis of PD was confirmed by neurological examination. Diabetes was defined by self-report, being on antidiabetic medication or diagnosis on medical records. Logistic regression analysis adjusted by potential confounders was performed to estimate the association between both conditions and also after dividing patients into short-duration (<10years) and long-duration (≥10years) diabetes. A total of 4998 subjects were included (79 PD and 4919 controls). Univariate analysis did not show any association between prevalence of PD and diabetes (OR 1.89, 95% CI 0.90-3.98, P=.09), although subgroup analysis showed a positive association in those with long-duration diabetes (3.27, 95% CI 1.21-8.85, P=.02). Diabetes duration might be an important factor in the association between PD and diabetes, and the risk might be limited to those with longer disease duration.

Next Generation Sequencing Data Analysis Evaluation in Patients with Parkinsonism from a Genetically Isolated Population

Parkinson's disease (PD) can be caused by genetic changes in a lot of genes. The effect of these changes is determined by the nature of the mutation and ranges from weak associations to pathogenic mutation which leads to loss of protein function. Our study is based on epidemiological data which show significantly increased prevalence of PD (2.9 %) in an isolated population of South-Eastern Moravia in the Czech Republic. We compared two different Next Generation Sequencing (NGS) data analysis approaches in DNA from 28 PD patients in the genes responsible for Parkinsonism (ADH1C, ATP13A2, EIF4G1, FBXO7, GBA + GBAP1, GIGYF2, HTRA2, LRRK2, MAPT, PARK2, PARK7, PINK1, PLA2G6, SNCA, UCHL1 and VPS35) using: 1) already described missense rare variants or pathogenic mutations 2) twelve control DNA samples from the same isolated population. Ion Torrent NGS data processing and trimming from Fastaq through “bam” to “vcf” files was done parallely by Torrent Suite/Ion Reporter and NextGENe software. After filtering out, three missense mutations were found in LRRK2 gene: rs33995883 in 6/0 patients/control (p/c); rs33958906 in 1/1p/c; rs781737269 in 3/0p/c; one missense mutation in MAPT gene rs63750072 in 6/1p/c; and one mutation in HTRA2 gene rs72470545 in 3/1p/c. Both the results from NextGENe with Ion Torrent adaptation and from Ion Reporter significantly correlated in variant calling. Our study may contribute to further explain the genetic background of Parkinsonism.

Descriptive study of the parkinsonian population in the north of France: Epidemiological analysis and healthcare consumption

BackgroundThe “neurodegenerative diseases plan” under elaboration for the Hauts-de-France region requires better knowledge of the patient population and care pathways. In France, the prevalence of Parkinson's disease (PD) has been estimated from cohorts to be about 1–3 per 1000 inhabitants, but exhaustive data are scarce for the general population. The purpose of this study was to evaluate the prevalence of PD in the Hauts-de-France region and to assess PD-related healthcare consumption. MethodA descriptive study was conducted to identify the parkinsonian population in the Hauts-de-France region (including the administrative districts of Pas-de-Calais and Picardie) for the year 2014. Parkinsonian patients were identified from health insurance fund reimbursement data using the following criteria: (i) reimbursement for a PD-specific medication; (ii) attribution of long-duration disease status coded as PD; (iii) hospital stay with PD diagnosis in the standard discharge report contained in the French medico-economic database on hospital activity (PMSI). ResultsThe raw prevalence of PD in the region was 5.03 per 1000 inhabitants aged 20 years and older. The standardized prevalence by health territory ranged from 4.0 to 9.0 per 1000 inhabitants aged 20 years and older. During the 1-year study period, 33.5% of patients had a neurology consultation, 57.1% attended a physiotherapy session, and 7.7% received speech therapy. Most of patients (79.6%) were treated with levodopa, sometimes in combination with a catechol-O-methyl transferase inhibitor (14.4%). Dopaminergic agonists were prescribed in 33.5% of cases. A neuroleptic was prescribed for 6.9% of the population (clozapine for 25.9%). ConclusionThe prevalence of PD is high in the Hauts-de-France region with a heterogeneous distribution by health territory. Neurology consultations were attended by a minority of patients in 2014. This work provides perspectives for necessary improvement in specialized care for this disease, both in terms of follow-up consultations and home care.

Parkinson Disease: An Evolutionary Perspective.

There are two central premises to this evolutionary view of Parkinson disease (PD). First, PD is a specific human disease. Second, the prevalence of PD has increased over the course of human history. Several lines of evidence may explain why PD appears to be restricted to the human species. The major manifestations of PD are the consequence of degeneration in the dopamine-synthesizing neurons of the mesostriatal neuronal pathway. It is of note the enormous expansion of the human dopamine mesencephalic neurons onto the striatum compared with other mammals. Hence, an evolutionary bottle neck was reached with the expansion of the massive nigrostriatal axonal arborization. This peculiar nigral overload may partly explain the selective fragility of the human dopaminergic mesencephalic neurotransmission and the unique presence of PD in humans. On the other hand, several facts may explain the increasing prevalence of PD over the centuries. The apparently low prevalence of PD before the twentieth century may be related to the shorter life expectancy and survival compared to present times. In addition, changes in lifestyle over the course of human history might also account for the increasing burden of PD. Our hunter-gatherers ancestors invested large energy expenditure on a daily basis, a prototypical physical way of life for which our genome remains adapted. Technological advances have led to a dramatic reduction of physical exercise. Since the brain release of neurotrophic factors (including brain-derived neurotrophic factor) is partially exercise related, the marked reduction in exercise may contribute to the increasing prevalence of PD.

Prevalence of Parkinson's disease: a population‐based study in Portugal

Portugal has been identified as one of the countries with a high prevalence of LRRK2-G2019S, considered to be the most frequent known cause of familial and sporadic Parkinson's disease (PD). The aim of this study was to evaluate the prevalence of PD in Portugal using a door-to-door methodology. A cross-sectional study was conducted in the Portuguese community-dwelling population; that is, elderly people living in the community on their own, aged ≥50years and resident in mainland Portugal, in two phases: (i) a questionnaire was applied to screen potential cases of PD; and (ii) screened cases were evaluated by an expert in PD to confirm diagnosis. The adjusted prevalence of PD for the Portuguese community-dwelling population aged ≥50years was 0.24%. The estimated total number of cases of PD for the Portuguese population is 180/100000 inhabitants. The results of this study show that a geographical region with a high frequency of a causal mutation for PD does not automatically imply a high prevalence of patients with PD.

Skin disorders in Parkinson's disease: potential biomarkers and risk factors.

Parkinson’s disease (PD) is one of the most common neurodegenerative disorders, characterized by a symptom triad comprising resting tremor, rigidity, and akinesia. In addition, non-motor symptoms of PD are well recognized and often precede the overt motor manifestations. Cutaneous manifestations as markers of PD have long been discussed, and cumulative evidence shows an increased prevalence of certain dermatological disorders in PD. Seborrheic dermatitis is considered to occur as a premotor feature of PD referable to dysregulation of the autonomic nervous system. Also, an increased risk of melanoma has been observed in PD. Light hair color is a known risk factor for melanoma, and interestingly the risk of PD is found to be significantly higher in individuals with light hair color and particularly with red hair. Furthermore, several studies have reported a high prevalence of PD in patients with bullous pemphigoid. Moreover, a 2-fold increase in risk of new-onset PD has been observed in patients with rosacea. Besides the association between PD and various dermatological disorders, the skin may be useful in the diagnosis of PD. Early PD pathology is found not only in the brain but also in extra-neuronal tissues. Thus, the protein α-synuclein, which is genetically associated with PD, is present not only in the CNS but also in the skin. Hence, higher values of α-synuclein have been observed in the skin of patients with PD. Furthermore, an increased risk of PD has been found in the Cys/Cys genotype, which is associated with red hair color. In this review, we summarize the current evidence of the association between PD and dermatological disorders, the cutaneous adverse effects of neurological medications, and describe the potential of skin protein expression and biomarkers in identification of risk and diagnosis of PD.

Epidemiology of Parkinson's disease.

Parkinson's disease (PD) affects 1-2 per 1000 of the population at any time. PD prevalence is increasing with age and PD affects 1% of the population above 60years. The main neuropathological finding is α-synuclein-containing Lewy bodies and loss of dopaminergic neurons in the substantia nigra, manifesting as reduced facilitation of voluntary movements. With progression of PD, Lewy body pathology spreads to neocortical and cortical regions. PD is regarded as a movement disorder with three cardinal signs: tremor, rigidity and bradykinesia. A recent revision of the diagnostic criteria excludes postural instability as a fourth hallmark and defines supportive criteria, absolute exclusion criteria and red flags. Non-motor symptoms in PD have gained increasing attention and both motor and non-motor signs are now included among the supportive criteria. The cause of PD is unknown in most cases. Genetic risk factors have been identified, including monogenetic causes that are rare in unselected populations. Some genetic factor can be identified in 5-10% of the patients. Several environmental factors are associated with increased risk of PD. Autopsy studies show that the clinical diagnosis of PD is not confirmed at autopsy in a significant proportion of patients. Revised diagnostic criteria are expected to improve the clinician´s accuracy in diagnosing PD. Increasing knowledge on genetic and environmental risk factors of PD will probably elucidate the cause of this disease within the near future.

The clinical features of Parkinson's disease in patients with mutations and polymorphic variants of GBA gene

Mutations in the glucocerebrosidase gene (GBA) increase the risk of Parkinson's disease (PD) by 6-10 times in all populations and are associated with the early-onset of PD, development of cognitive impairment and presence of psychotic disorders. At the same time, polymorphic variants associated with the twofold increase in the risk of PD were also described in the GBA gene. To estimate the clinical features of PD in patients with mutations and polymorphic variants of the GBA gene. Evaluation of motor, cognitive, emotional, psychotic and autonomic dysfunctions in patients with mutations (N370S, L444P) and polymorphic variants (E326K, T369M) in the GBA gene was performed using clinical scales. Patients with mutations (mGBA-PD), and with polymorphic variants (pGBA-PD) in the GBA gene were compared with the group of patients with sporadic PD (sPD). Compared to sPD, affective disorders (depression and anxiety) were more expressed in the mGBA-PD group (p=0.001) and the general GBA-PD group (p=0.001) assessed with Sheehan anxiety rating scale, in the pGBA-PD group (p=0.012) and the general GBA-PD group (p=0.05) assessed with the NPI, in the mGBA-PD (p=0.003), pGBA-PD (p=0.022), and general GBA-PD groups (p=0.001) assessed with the Hospital Anxiety and Depression scale (HADS 'A'), and in the pGBA-PD group (p=0.005) assessed with the HADS 'D'. Non-motor symptoms assessed with the PD-NMS were more expressed in the pGBA-PD patients (p=0.007) and in the total group with GBA-PD (p=0,014) compared to sPD. Cognitive impairment measured with MMSE was more marked in mGBA-PD patients (p=0.022). Differences in motor and non-motor clinical symptoms between pGBA-PD and mGBA-PD groups were not found. Thus, clinical features of non-motor symptoms were described both in carriers of GBA mutations and polymorphisms. Identification of the specific clinical phenotype of PD in carriers of GBA polymorphic variants is important due to their relatively high prevalence in PD patients.

A Short Commentary on the Racial Disparities in Parkinson’s Disease

The etiology of Parkinson Disease (PD) remains elusive, but may include environmental and genetic factors leading to neuronal degeneration [1]. The difference in incidence of PD among different racial groups may provide additional insight into the etiology. In 2004, McInerney-Leo et al. reviewed twenty studies analyzing the prevalence and incidence of PD among Caucasians, African-Americans in the United States and African populations [2]. The differences in prevalence of Parkinson’s disease and Parkinsonism could not be demonstrated because of poor designs and numerous biases, such as referral bias and differences in access to healthcare. Therefore, they were unable to determine the effect of race in PD. Yet, studies continue to suggest that there is a significantly higher prevalence of PD among Caucasians compared to other racial groups [3]

Nonmotor Symptoms in Parkinson's Disease: Gender and Ethnic Differences.

Nonmotor symptoms (NMS) are recognized to profoundly affect the quality of life of patients with Parkinson's disease (PD) and of their caregivers. In order to further understand the underlying pathophysiology, clinical presentation, response to medication, and prognosis, it is important to identify and analyze possible factors, which have an impact on PD. Gender and ethnicity have been reported to possibly influence incidence, prevalence, and motor presentation in PD, as well as other neurological conditions. However, the impact of gender and ethnicity on the presentation of NMS in PD is currently unclear. In this chapter, the currently available knowledge about gender and ethnic differences in NMS in PD will be summarized and possible factors that might contribute to those observed differences will be discussed.

Racial Demographics in an Urban Movement Disorders Clinic

Objective: To assess the prevalence of Parkinson’s disease (PD) among African- Americans compared to non-Hispanic Whites in a tertiary urban Movement Disorders center. Background: Contributing factors in the prevalence of Parkinson’s disease (PD) based on race may improve health disparities in the United States. According to the largest study analyzing prevalence and incidence of PD among Medicare beneficiaries, the ratio of African-Americans (AA) to Caucasians in the general Medicare population is 9%, while the prevalence ratio of PD among AA compared to Caucasians is approximately 5%. Methods: We performed a retrospective analysis of African-American patients with PD in the movement disorders database at Boston Medical Center, which is the largest safety net hospital in New England. The demographics of the patients seen in the general neurology clinic are 30.57% AA and 38.06% non-Hispanic Caucasian. Results: The Movement disorders database included 488 patients, 327 of whom had PD. Of these, 287 were Caucasians and 18 were of African descent. Based on our clinic population the expected PD case ratio among AA compared to Caucasians was approximately 49%. The actual race ratio in patients of African descent compared to Caucasian was 6%, which was substantially lower than expected at Boston Medical Center. Conclusion: The demographics of the PD patients in our movement disorders clinic do not reflect the population at Boston Medical Center, or the demographics of our neurology clinic as a whole.

Treatment of Older Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. The prevalence of PD increases with age. The spectrum of clinical features, the rate of progression of the disease, the burden of nonmotor symptoms, and the response to medications are different in older patients with PD from the relatively younger patients. Management of symptoms of PD in older patients is challenging because of possible existence of several age-related systemic illness. While dealing with older patients, it is crucial not to attribute all the physical symptoms to PD. Thorough evaluation for existence of diseases such as normal pressure hydrocephalus and vascular parkinsonism which partially mimic the symptoms of PD carries immense importance. Medical management of parkinsonian symptoms should be preferred with levodopa monotherapy. However, in patients with significant motor fluctuations, dopaminergic agents may be added with caution, as they are notorious for several adverse reactions. Nonmotor symptoms must be provided high importance as they substantially worsen the quality of life. In addition to parkinsonian symptoms, older patients with PD may need to undergo surgery for several conditions. Meticulous perioperative management is crucial as older patients with PD may face several surgery-related complications compared to the younger patients. Compliance to treatment is an important issue in old age. Hence multidisciplinary approach to management of PD in older patients should be emphasized.

Epidemiology of Parkinson's Disease: A Population-Based Study in Primary Care in Italy

Background: There are no studies on prevalence, incidence and comorbidities of Parkinson's disease (PD) in the Italian population. Methods: The database of 700 Italian general practitioners (population, 923,356) was investigated. All patients with International Classification of Diseases Ninth Revision - Clinical Modification (ICD-9-CM) diagnosis of PD during the period 2002-2012 were included. Parkinsonisms were excluded. Clinical conditions preceding PD were identified through ICD-9-CM codes. The Charlson Comorbidity Index was used. PD crude and standardized prevalence and annual incidence were calculated. Crude and adjusted hazard ratios were calculated for comorbidities. Results: A total of 2,204 patients (1,140 men, 1,064 women, age 22-95 years) were included. The crude prevalence of PD was 239/100,000. Prevalence increased exponentially with age. Standardized prevalence was 233 (95% CI 232-235). One hundred ninety-four patients were newly diagnosed, giving a crude incidence of 22/100,000 and a standardized incidence of 23.1/100,000 (95% CI 22.9-23.2). Incidence increased steadily until age 75-84 years and then decreased. Older age, cardiovascular and gastrointestinal disorders, diabetes, and restless-legs syndrome were associated with increased PD risk and smoking and hypersomnia with decreased PD risk. The Charlson Comorbidity Index was associated with PD risk with a documented gradient. Conclusions: Prevalence and incidence of PD in Italy are in line with studies with the highest case ascertainment. PD risk varies with the number and type of comorbidities.

SIPA1L2, MIR4697, GCH1 and VPS13C loci and risk of Parkinson's diseases in Iranian population: A case-control study

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Prevalence of PD increases steadily with age. A recent meta-analysis of genome-wide association studies has identified six new loci to be linked with PD. Here we investigated the association of four of these new loci, SIPA1L2, MIR4697, GCH1 and VPS13C with PD in an Iranian population. Through a case-control study a total of 1800 subjects comprising 600 PD patients and 1200 unrelated healthy controls were recruited. Rs10797576, rs329648, rs11158026 and rs2414739 related to SIPA1L2, MIR4697, GCH1 and VPS13C loci respectively, were genotyped in all subjects. The difference of genotype and allele frequencies between case and control groups were investigated using chi-square test and logistic regression models with R software. Genotype and allele frequencies were significantly different in PD patients and control group for rs329648, rs11158026 and rs2414739 (p-value=0.018, 0.025, and 0.009 respectively for allele frequency differences). There was no difference in genotype nor allele frequencies between the two groups for rs10797576.We replicated the association of three new loci which are proposed for PD. More studies in other populations and also functional analysis are required to clear the role of these variants in PD.

Parkinson’s disease in the older patient

Parkinson's disease (PD) is the second most commonly encountered neurodegenerative condition in clinical practice and probably offers a significantly greater variety of challenges than the management of Alzheimer's disease. As with most neurodegenerative diseases, age represents the leading risk factor for the development of PD. Current estimates would suggest that PD affects 1-2% of people over the age of 65years and each decade sees an increasing number of cases. In addition, it is well recognised that most industrialised nations have an increasing proportion of individuals living longer. For example, recent data from Australia indicates that the prevalence of PD is anticipated to rise by 80% over the next 20years and as such, we must all strive towards improving our clinical management of this common condition. In this article, we will attempt to highlight the issues that should be actively sought out and, where possible, addressed. We hope that an improved level of understanding will lead to better outcomes in older patients with PD.

A door-to-door survey to estimate the prevalence of Parkinsonism in Pakistan.

IntroductionParkinson’s disease (PD) occurs in all races and cultures, and population-related differences in frequency may provide etiological clues. The present study was designed to explore the prevalence of PD and Parkinsonism in Pakistan, the world’s sixth most populous country, for which no published prevalence data are available.MethodsWe conducted a three-phase door-to-door survey in two districts of the Khyber Pakhtunkhwa province of Pakistan, to assess the prevalence of PD and Parkinsonism in a sample of 4,000 individuals aged 50 years and above.ResultsWe identified 14 cases of Parkinsonism, eleven with a diagnosis of idiopathic PD. The overall prevalence estimates were 1.7/100 (95% confidence interval [CI]: 0.9–2.46) for Parkinsonism and 1.28/100 (95% CI: 0.6–1.94) for PD in persons aged 65 years and above. The age-standardized prevalence of PD (aged 65 years and above), normalized to the USA population in 2000, was 1.33/100, which is similar to that observed in other human populations. Of the total 14 cases, five were newly diagnosed and four had a family history of PD.ConclusionThe estimated prevalence rates in Pakistan are similar to those observed in other human populations. The frequency of familial Parkinsonism is also equivalent to previous estimates.

Trinucleotide repeat expansion of TATA-binding protein gene associated with Parkinson's disease: A Thai multicenter study

IntroductionSpinocerebellar ataxia type 17 (SCA17) is an inherited cerebellar degeneration associated with trinucleotide repeat expansions in the TATA-binding protein gene (TBP). Low-range expansions of TBP have recently been described in association with Parkinson's disease (PD). However, these low-range expansion alleles were also observed in healthy individuals. Prior distinct findings may result from reduced penetrance or age-dependent susceptibility, which may influence phenotypic expression. MethodsA case-control study of 456 PD patients and 374 control subjects was conducted. Data and blood samples were collected during 2008–2013. Control subjects were individuals over 65 years old without parkinsonism. Sizes of TBP trinucleotide repeats were analyzed. All available carriers of the TBP repeat of ≥40 repeats were re-examined. ResultsA high prevalence of carriers of TBP repeat expansion ≥41 developed PD, mainly at an advanced age. Half of these carriers had onset after 70 years of age (range 34–84). Seven participants carried expansion alleles of ≥42, and all had PD. Fourteen participants (six patients and eight controls) carried a heterozygous 41-repeat allele. At the current mean age of 79 years and mean follow-up period of 4 years, three out of the eight control carriers of the 41-repeat allele developed PD, while none of the thirteen asymptomatic carriers of the 40-repeat allele did. ConclusionsA high prevalence of PD was observed in carriers of low-range expansions of TBP (41–45 repeats), especially in elderly. This finding suggests that cut-off value for pathological TBP repeat expansion appear to be 41.

Estimating the prevalence of Parkinson's disease (PD) and proportions of patients with associated dementia and depression among the older adults based on secondary claims data.

While the epidemiology of Parkinson's disease (PD) has been extensively studied, data on the prevalence of PD among the older adults in Germany are scarce, based on small samples, and limited to primary data designs. This study estimated the PD prevalence among the older adults in Germany in 2006 using secondary data. We included 815,573 health insurance members aged ≥65 years from all regions in Germany. PD was identified in case of at least one inpatient or outpatient diagnosis. An outpatient diagnosis had to be confirmed by either a subsequent diagnosis or an antiparkinsonian drug within 12 months. PD was also assumed if a first prescription was confirmed by a diagnosis within 12 months. Cases were checked for a diagnosis of dementia or depression. The standardized prevalence of PD was 1680 (95% confidence interval (CI): 1644-1716) cases per 100,000 persons. The prevalence increased with age and peaked in the age group of ≥90 years (4633 cases; 95% CI: 4227-5068) with higher rates in men (1729; 95% CI: 1684-1776) than in women (1644; 95% CI: 1593-1697). Dementia and depression occurred in 26.6% (95% CI: 25.8-27.5) and 32.6 (95% CI: 31.7-33.5) of PD cases, respectively. The age-related increase of PD prevalence and the age-specific prevalence estimates are in line with other European studies, stressing the public health relevance related to PD. In addition to the minimization of biases that might occur in primary data studies, further strengths of our findings are the large underlying sample size and the coverage of Germany.

Differential expression of calbindin in nigral dopaminergic neurons in two mice strains with differential susceptibility to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

Parkinson’s disease (PD) affects the A9 dopaminergic (DA) neurons of substantia nigra pars compacta (SNpc) whereas other DA neuronal subtypes are spared. The role of calbindin in this differential vulnerability has been long elicited, and is seen in the MPTP induced mice models of PD. A peculiar feature of mice models is the strain specific differences in the susceptibility to MPTP. Here, calbindin-D28K expression in DA neurons of SNpc of MPTP susceptible C57BL/6 mice and MPTP resistant CD-1 mice was studied as a susceptibility marker of degeneration. Unbiased stereological estimation of immunoperoxidase stained midbrain sections revealed significantly higher number of calbindin immunoreactive cells in SNpc of CD-1 mice compared to that of C57BL/6 strain. Western blotting showed minimal differences in the levels. Calbindin–tyrosine hydroxylase immunofluorescence co-labeling was performed to map the calbindin immunoreactive DA neurons in SNpc and ventral tegmental area (VTA) and to quantify the calbindin expression at cellular level. While the levels were comparable in VTA of both mice strains, the SNpc of CD-1 mice showed significantly higher calbindin expression. Within the SNpc, the medial and dorsal subdivisions showed higher calbindin expression in CD-1. The expression in the ventrolateral SNpc of both strains remained comparable. Our observations clearly point at overall higher levels and sizeable percentage of cells expressing more calbindin in SNpc of CD-1 mice, which might confer neuroprotection against MPTP, while its lower expression makes C57BL/6 mice more susceptible. Similar mechanism may be attributed to the phenomenon of differential prevalence of PD in different ethnic populations.