Factors influencing the development of early- or late-onset Parkinson's disease in a cohort of South African patients
ABSTRACT Background. Neurodegenerative disorders such as Parkinson's disease (PD) contribute significantly to global disease burden. PD can be categorised into early-onset PD (EOPD) with an age at onset (AAO) of ≤50 years and late-onset PD (LOPD) with an AAO of 50 years. Aims. To identify factors influencing EOPD and LOPD development in a group of patients in South Africa (SA). Methods. A total of 397 unrelated PD patients were recruited from the Movement Disorders Clinic at Tygerberg Hospital and via the Parkinson's Association of SA. Patient demographic and environmental data were recorded and associations with PD onset (EOPD v. LOPD) were analysed with a Pearson's Chi-squared test. The English- and Afrikaans-speaking (Afrikaner) white patients were analysed separately. Results. Logistic regression analysis showed that ethnicity (p<0.001) and family history (p=0.004) were independently associated with AAO of PD. Average AAO was younger in black, coloured and Afrikaner patients than English-speaking white patients. A positive family history of PD, seen in 31.1% of LOPD patients, was associated with a younger AAO in the study population. Conclusions. These associations may be attributed to specific genetic and/or environmental risk factors that increase PD susceptibility and influence the clinical course of the disorder. More studies on PD in the unique SA populations are required to provide novel insights into mechanisms underlying this debilitating condition.
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ABSTRACT: Young onset Parkinson's disease is more likely to be genetic than older onset Parkinson's disease, particularly with a positive family history, and there are also racial differences.(1 2) Both autosomal dominant and recessive causes of Parkinson's disease are described; analysis of family history data is instructive regarding genetic risk and likely inheritance patterns. Detailed family histories were obtained from young onset (<50 years old) Parkinson's disease patients by the Parkinson's Repository of Biosamples and Networked Datasets (PRoBaND) clinical consortium. In 240 cases enrolled, the mean age of onset of Parkinson's disease was 43.6 years (SD 5.8), mean disease duration was 10.2 years (SD 6.8) and 69.3% are male. Most (94.1%) were Caucasian; the largest ethnicity was white British (89.1%); 3.2% were of Asian, and 0.5% of African heritage. There was a family history of Parkinson's disease in one or more first degree relative in 12.5%, one or more second degree relative in 13.3%, and one or more family members had Parkinson's disease in 23.7% of the index cases (Figure). The positive first degree family history was parental in 10.8% of patients, in one or more siblings in 2.5% of cases, and one or more children in <0.5% of cases. 5.8% had a maternal grandparent, and 2.9% had a paternal grandparent with PD. Positive family histories in about a quarter of young onset PD patients is similar to previous studies.(3) Around one tenth of patients in this population may have autosomal dominant inheritance. Far fewer have a family history pattern suggesting autosomal recessive inheritance, but this may be underestimated from family tree assessment. Genetic testing is now underway in our cohort, both for known genes including GBA, LRRK2, PARKIN, PINK1, and SNCA, but also for the analysis of genetic variation (single nucleotide polymorphism) that may be of greater significance to the presence and severity of disease-related complications, such as cognitive impairment and therapy responses.Journal of neurology, neurosurgery, and psychiatry 11/2013; 84(11):e2. DOI:10.1136/jnnp-2013-306573.160 · 5.58 Impact Factor
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ABSTRACT: Background Sub-Saharan African (SSA) countries are experiencing rapid transitions with increased life expectancy. As a result the burden of age-related conditions such as neurodegenerative diseases might be increasing. We conducted a systematic review of published studies on common neurodegenerative diseases, and HIV-related neurocognitive impairment in SSA, in order to identify research gaps and inform prevention and control solutions. Methods We searched MEDLINE via PubMed, ‘Banque de Données de Santé Publique’ and the database of the ‘Institut d’Epidemiologie Neurologique et de Neurologie Tropicale’ from inception to February 2013 for published original studies from SSA on neurodegenerative diseases and HIV-related neurocognitive impairment. Screening and data extraction were conducted by two investigators. Bibliographies and citations of eligible studies were investigated. Results In all 144 publications reporting on dementia (n = 49 publications, mainly Alzheimer disease), Parkinsonism (PD, n = 20), HIV-related neurocognitive impairment (n = 47), Huntington disease (HD, n = 19), amyotrophic lateral sclerosis (ALS, n = 15), cerebellar degeneration (n = 4) and Lewy body dementia (n = 1). Of these studies, largely based on prevalent cases from retrospective data on urban populations, half originated from Nigeria and South Africa. The prevalence of dementia (Alzheimer disease) varied between <1% and 10.1% (0.7% and 5.6%) in population-based studies and from <1% to 47.8% in hospital-based studies. Incidence of dementia (Alzheimer disease) ranged from 8.7 to 21.8/1000/year (9.5 to 11.1), and major risk factors were advanced age and female sex. HIV-related neurocognitive impairment’s prevalence (all from hospital-based studies) ranged from <1% to 80%. Population-based prevalence of PD and ALS varied from 10 to 235/100,000, and from 5 to 15/100,000 respectively while that for Huntington disease was 3.5/100,000. Equivalent figures for hospital based studies were the following: PD (0.41 to 7.2%), ALS (0.2 to 8.0/1000), and HD (0.2/100,000 to 46.0/100,000). Conclusions The body of literature on neurodegenerative disorders in SSA is large with regard to dementia and HIV-related neurocognitive disorders but limited for other neurodegenerative disorders. Shortcomings include few population-based studies, heterogeneous diagnostic criteria and uneven representation of countries on the continent. There are important knowledge gaps that need urgent action, in order to prepare the sub-continent for the anticipated local surge in neurodegenerative diseases.BMC Public Health 06/2014; 14(1):653. DOI:10.1186/1471-2458-14-653 · 2.32 Impact Factor