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April 07, 2003

Shaking it up

FuturePundit (a.k.a. SARSPundit) points me to this article that indicates some interesting patterns in Parkinson's Disease:

The scientists examined the mitochondrial DNA of 609 Parkinson's disease patients and 340 normal controls who had no signs of the disease. In particular, they looked at nine well-known and well-studied gene variations that vary among ethnic groups. When they looked at the correlation between gene variation and incidence of Parkinson's disease, they discovered that one variant, called "J" was much more common in people who do not have Parkinson's disease, and particularly among women.

"The J haplogroup is much more common in unaffected individuals, so that would suggest it is protective," said Vance.

The J variant is found in about 26 percent of Caucasians, versus two-thirds of Asians and more than 90 percent of sub-Saharan Africans. However, the researchers noted that since they only studied Caucasians in this study, they could venture no conclusion about whether the J variant is protective in other ethnic groups.

Posted by razib at 12:32 AM

Paradoxes in longevity: sequence analysis of mtDNA haplogroup J in centenarians

Giuseppina Rose et al.

EJHG, September 2001, Volume 9, Number 9, Pages 701-707

Previous studies have shown that mitochondrial DNA (mtDNA) haplogroup J is significantly over-represented in healthy centenarians with respect to younger controls, thus suggesting that this haplogroup predisposes to successful aging and longevity. On the other hand, the same haplogroup is reported to have elevated frequency in some complex diseases. To verify if centenarians clustered in a particular lineage within J we have sequenced the D-loop region from 18 centenarians and 18 younger controls, previously characterized to be J. Then the entire mtDNA molecule was sequenced in a sub-sample of nine centenarians to find possible functional mutations associated with haplogroup J in successful aging. No clustering of the J haplogroup mtDNA from centenarians was observed. In addition, most of the mutations found are known as disease-associated mutations. The general picture that emerges from the study is that the J haplogroup of centenarians is surprisingly similar to that found in complex diseases, as well as in Leber Hereditary Optic Neuropathy. This finding implies that the same mutations could predispose to disease or longevity, probably according to individual-specific genetic backgrounds and stochastic events. This data reveals another paradox of centenarians and confirms the complexity of the longevity trait. European Journal of Human Genetics (2001) 9, 701-707.

Posted by: Dienekes at April 7, 2003 03:01 AM

BTW, haplogroup J is generally not found in East Asians or Africans. That part of the article is most probably wrong. It is found in the highest frequencies (~70%) in the Near East.

Posted by: Dienekes at April 7, 2003 03:05 AM