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Genetic Information on Major Diseases Uncovered

Posted by Zonk on from the oh-genes-not-jeans dept.

gollum123 writes "A major advance in the genetic understanding behind several of the world's most common diseases is being reported by the BBC. A study tested some 17,000 people to find genetic markers for the various diseases. 'They found new genetic variants for depression, Crohn's disease, coronary heart disease, hypertension, rheumatoid arthritis and type 1 and 2 diabetes. The Wellcome Trust Case Control Consortium (WTCCC) involved 50 leading research groups analyzing the DNA from 2,000 patients for each of the seven conditions and 3,000 healthy volunteers. One of the most exciting finds was a previously unknown gene common to type 1 diabetes and Crohn's disease, a type of inflammatory bowel disorder, suggesting that they share similar biological pathways.' There is also disease by disease data at the BBC."

1 of 176 comments (clear)

  1. Replication of Results? by dorpus · · Score: 3, Informative

    Speaking as a statistical genetics insider, I can tell you that the replication of results in this field is very poor. A team of scientists somewhere will announce they found a gene for XYZ, which is reported in scientific journals and mainstream media -- however, the findings fail to be replicated by other scientists, and the negative results are usually not published. Over the years, hundreds of scientists have claimed to find genes responsible for diabetes, hypertension, autism, etc.

    Since there are tens of thousands of genes in the genome, a study with 17,000 subjects makes for less than one subject per gene. (Exactly how many "genes" are in the genome anyway? What exactly defines a "gene"? That is another vast topic.)

    Statistically speaking, there should be at least ten subjects per covariate (gene) tested. There is a great deal of hoo-haa over microarrays, but the more you learn about microarrays, the more you will learn just how unreliable they are. The same "disease" can have vastly different pathophysiologies and genetic origins across population groups. Epigenetics, penetrance, expressivity, intron effects -- all multiply the complexity exponentially.

    In short, genetics is to biology what nuclear fusion is to physics -- a promising technology that will remain a "few years away" for decades to come.