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| Parkinson's Disease - Genetic
& Environmental aetiology Low prevalence of Parkinsons's disease among Indians Home Medi News |
Parkinson's
Disease - Genetic & Environmental aetiology Parkinson's disease is likly to be a multifactoral disorder involving a combination of environmental and genetics factors. The cause of PD is unknown. Various factors have been implicated in the aetiology of the disease, such as infection, metabolic factors, free radiacals, growth factors and toxins. Until recently research mainly focused on connection between this disorder and environmental factors such as viral infection and neurotoxins. In the last few years studies have show linkage between genetic factors and movement disorders, because of this interest has shifted from environment to genome. In 1997, a study funded by the National Institute of Health in the US reported that a family of Greek and Italian origin with a parkinsonian syndrome had an abnormal gene on chromosome 4 which produced a protien called alpha-synuclein. This family was atypical because of relatively young mean age of onset of 45 years and the rapid course of 10 years from the onset to death. However, in over 200 familial cases of PD, studies by other groups, parkinsonism was not linked to the 4q-locus. Work done by different groups have shown linkage of PD with other chromosomes 2 and 6. The demonstration of three different genes, on 3 different chromosomes, producing parkinsonism, shows that there are multiple causes even within genetic category. There are certainly multiple genetic causes but in all probability in majority of patients there are significant non-genetic causes. It may be that there are several different environmental risk factors just as ther are several different genes on several different chromosomes which establish the background of susceptibility to Parkinson's disease. The liability to develop the disease will depend on what one might say the dose of environmental factor and the dose of genetic predisposition combined. ALso see: Parkinson's Gene Low prevalence of Parkinsons's disease among Indians is said to be due to the presence of some protective factors in the brain that inhibit the pathological changes leading to Parkinson's disease. Prevelance ratio: North Americans: 280/100,000 Africans: 59/100,000 Chinese: 44/100,000 Indians: 19/100,000. Parsis living in India have the highest recorded prevalence rate of 328/100,000. ( Parsis migrated to India from Persia now Iran. )
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