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“Familial Parkinson's Disease” – A Case-Control Study of Families
- Ryan J. Uitti, Hitoshi Shinotoh, Margo Hayward, Michael Schulzer, Edwin Mak, Donald B. Calne
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- Journal:
- Canadian Journal of Neurological Sciences / Volume 24 / Issue 2 / May 1997
- Published online by Cambridge University Press:
- 18 September 2015, pp. 127-132
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- Article
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Background:
Parkinson's disease (PD) patients frequently report a family history of PD and this may provide etiological clues to PD. It has also been suggested that a report of a negative family history is reliable. We studied the prevalence of PD in relatives of PD patients to assess the reliability of family history and to evaluate possible explanations of “familial PD”(fPD).
Methods:81 of 650 (12.5%) PD probands (all PD patients seen at clinic in 4 years) reported a positive family history of PD. Each fPD proband was matched with non-familial PD (nfPD) proband by gender and year of birth. Screening and follow-up questionnaires were mailed to relatives to obtain information concerning pedigree and presence of neurodegenerative disease. Available family members (regardless of disease status) were examined.
Results:On examination, 8 persons, said to be “normal” by probands, relatives and themselves, had definite or possible PD (5 fPD, 3 nfPD). The prevalence rate of PD among first and second degree living relatives of probands varied significantly between fPD and nfPD groups (6269/100 000 versus 1190/100 000; p < 0.001). The weighted prevalence (taking into account the proportions of fPD and nfPD within the clinic) was 1822/100 000, a value more than 5 times higher than reported prevalence rates of PD in the general population (p < 0.001). The prevalence rate was greater in first degree relatives than second degree.
Conclusions:“Familial parkinsonism” cannot be explained merely by size of or advanced age within families. Significant numbers of previously unrecognized PD patients may be identified despite a “negative” family history. That is, the patient's report of an absence of familial parkinsonism is frequently inaccurate. The prevalence rate in relatives of PD patients appears to be higher than the general population – regardless of the family history reported by a PD patient. We believe our study suggests that genetic influences or early life environmental exposures are likely to be of etiological importance in PD.
A puzzling Hex primer
- Edited by Michael H. Albert, University of Otago, New Zealand, Richard J. Nowakowski, Dalhousie University, Nova Scotia
- Mathematical Sciences Research Institute
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- Book:
- Games of No Chance 3
- Published online:
- 28 February 2011
- Print publication:
- 29 May 2009, pp 151-162
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Summary
Abstract. We explain some analytic methods that can be useful in solving Hex puzzles.
Introduction
Solving Hex puzzles can be both fun and challenging. In this paper – a puzzling companion to Hex and Combinatorics and Dead Cell Analysis in Hex and the Shannon Game, both written in tribute to Claude Berge – we illustrate some theoretical concepts that can be useful in this regard.
We begin with a quick review of the rules, history, and classic results of Hex. For an in depth treatment of these topics, see.
The parallelogram-shaped board consists of an m × n array of hexagonal cells. The two players, say Black and White, are each assigned a set of coloured stones, say black and white respectively, and two opposing sides of the board, as indicated in our figures by the four stones placed off the board. In alternating turns, each player places a stone on an unoccupied cell. The first player to connect his or her two sides wins.
In the fall of 1942 Piet Hein introduced the game, then called Polygon, to the Copenhagen University student science club Parenthesis. Soon after, he penned an article on the game for the newspaper Politiken. In 1948 John Nash independently reinvented the game in Princeton, and in 1952 he wrote a classified document on it for the Rand Corporation.
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