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Dear Scott Your explanation and interpretation are very logical and interesting. I have always wondered whether cousin marriages lead to higher incidence of genetically-related medical disorders - even though it is difficult to prove. Over here in Malaysia, our study revealed that the percentage of Parkinson's patients among our patients is only 2% (among the first-degree relatives) despite a high mean no of siblings. This suggested that genetic factor also played only a minor role in the causation of PD in Malaysia. Consanguineous marriage was seen in 2% of our patients. I thought about cousin marriage because it is relatively more common to see it in Asian countries. Over here in Asian region, cousin marriage is not so commonly considered "immoral" or "incestuous". Scott and Ray, thank you for the interesting discussion. Dr Chew > Date: Sun, 2 Aug 2009 20:11:43 -0700 > From: [log in to unmask] > Subject: Re: Amish got PD > To: [log in to unmask] > > Dr. Chew, > > As you might know, cousin marriage is a common (in fact, preferred) practice in many parts of the world. Marriage between cross cousins (father's sister's child or mother's brother's child) and/or parallel cousins (father's brother' child and/or mother's sister's child) is pretty much the rule in all band-level societies, and many tribal-level societies. (In popular terms, these all are first cousins.) In other words, it probably was common among all our ancestors. > > Cousin marriage is legal in more than half of the United States, but generally is not socially acceptable. It occurs here only rarely. At least, we hear about it only rarely, since many people who marry their cousins are not likely to say anything about it, in fear of negative social reaction. Still, I have not seen any good evidence to show that marriage between first or second cousins has any more negative results in offspring than in the general population. (That doesn't mean such evidence does not exist.) > > In the Amish case, we simply do not have enough information to point to a most likely cause of the high incidence of PD among those people. The possibilites, of course, include genetics, environment, and lifestyle. In terms of genetics, I have some familiarity because I lived among the Amish in Ohio. According to Amish religion, first-cousin marriages are forbidden. Second-cousin marriage do occur, but infrequently. These two facts alone would convince me that a genetic cause is unlikely. Still, one additional fact makes genetics a strong possibility: Amish marry endogamously. In other words, Amish marry Amish. > > Thus, Amish people have a limited gene pool, making genetic transmission of any disorder more likely than in the general population. So, a genetic link might have nothing to do with marriage between cousins, and more to do with marriage within a communal population. > > Be well. Scott > > Scott E. Antes > Northern Arizona University > Department of Anthropology > PO Box 15200 > Flagstaff, AZ 86011 > ________________________________________ > From: Parkinson's Information Exchange Network [[log in to unmask]] On Behalf Of chew nee kong [[log in to unmask]] > Sent: Sunday, August 02, 2009 2:30 AM > To: [log in to unmask] > Subject: Re: Amish got PD > > Dear Ray > > Could this high prevalence of PD be due to genetic factor such as cousin marriage? I heard that cousin marriage is legal in some parts of the US. > > Dr Chew > > > Date: Sat, 1 Aug 2009 09:53:01 -0700 > > From: [log in to unmask] > > Subject: Amish got PD > > To: [log in to unmask] > > > > > > from Viartis: > > > > 1st August 2009 - New research > > THE WORLD'S HIGHEST PREVALENCE OF PARKINSON'S DISEASE > > Neuroepidemiology [2009] 33 (3) : 225-230 (Racette BA, Good LM, Kissel AM, > > Criswell SR, Perlmutter JS.) Complete abstract > > > > The world's highest prevalence of Parkinson's Disease by far has been found > > among the Amish religious community, where Parkinson's Disease is two to > > three times more prevalent than anywhere else in the world. > > The Amish are primarily in the North East of the U.S.A. They are a devoutly > > religious community who believe in the literal interpretation of the Bible. > > They segregate themselves from other communities, wear traditional clothes, > > and live a traditional lifestyle that does not permit the use of > > electricity, television, radio, or telephones. For transport they use horses > > and carriages instead of cars, which they are not allowed to use. Most speak > > a German dialect known as Pennsylvania Dutch. For more information click > > here and here, and for a brief video of their lifestyle click here. > > > > The prevalence of Parkinson's Disease amongst the Amish aged 60 or older has > > been found to be 5,703 per 100,000, which is enormously high. According to > > U.N.Data, 17% of the U.S. population is aged 60 or older. So the prevalence > > of Parkinson's Disease in the Amish community as a whole is 970 per > > 100,000. This is by far the highest prevalence of Parkinson's Disease in the > > world, and around three times the prevalence of the U.S.A., despite the > > U.S.A having the highest prevalence of any country. For more information go > > to the Prevalence of Parkinson's Disease. The Amish refuse to take out > > health insurance. They are also afflicted by genetic disorders. So it was > > thought that the cause might be genetic. However, the more closely related > > they were, the less they were affected. They are primarily involved in > > agriculture, and most of them use pesticides, but the effect of pesticides > > was not assessed by the researchers. In order to refer to this article on > > its own click here. > > > > Rayilyn Brown > > Director AZNPF > > Arizona Chapter National Parkinson Foundation > > [log in to unmask] > > > > ---------------------------------------------------------------------- > > To sign-off Parkinsn send a message to: mailto:[log in to unmask] > > In the body of the message put: signoff parkinsn > > _________________________________________________________________ > Share your memories online with anyone you want. > http://www.microsoft.com/malaysia/windows/windowslive/products/photos-share.aspx?tab=1 > ---------------------------------------------------------------------- > To sign-off Parkinsn send a message to: mailto:[log in to unmask] > In the body of the message put: signoff parkins > > ---------------------------------------------------------------------- > To sign-off Parkinsn send a message to: mailto:[log in to unmask] > In the body of the message put: signoff parkinsn _________________________________________________________________ With Windows Live, you can organize, edit, and share your photos. http://www.microsoft.com/malaysia/windows/windowslive/products/photo-gallery-edit.aspx ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn