i have three friends with ms. i have always wondered why this happened to them. i hope that someday, we will have an answer.
on the surface the story in wired made perfect sense: twin study deepens multiple sclerosis mystery. it is about a new study from the national center for genome resources that compared the genetic endowments of three sets of identical twins, one each of which contracted multiple sclerosis (ms), the other didn't. this was a full bore effort that wound up costing $1.5 million over a year and a half to sequence 2.8 billion base pairs in each twin, determine if they come from the mother or father and then -- and this is the amazing part -- determine the entire epigenome of the cd4 cell, one of the white cells in the immune system that plays a central part in ms. ms is thought to be an autoimmune disease where the patient aberrantly makes antibodies to his or her own nerve tissues. the epigenome consists in additional modifications to the genome that are acquired throughout life that don't involve the underlying sequence. they often involve attaching other small molecular groups, like the methyl group, onto the basic sequence without altering it. twins have identical genomes but their epigenomes might diverge as they age and they encounter different environmental influences. so looking for the answer in the epigenome made a lot of sense. but the answer wasn't there. there was no difference in either the genomes (expected) or the epigenomes, or, for that matter, in the transcriptomes, the repertoire of what genes are actually expressed. each twin looked the same but only one had ms.
as i say, that this surprise made sense on one level. it was a reasonable place to look. but i found another aspect of the story quite striking:
it's still possible that some as-yet-unknown genetic factor, undetectable by even the most advanced tools, may explain the discordance in the study. however, [lead author and geneticist stephen] kingsmore thinks the culprit is probably an unknown environmental influence. "there must be a nongenetic factor, probably environmental," that combines with known genetic and environmental risks, he said. (brandon keim, wired)
the editors of effect measure are senior public health scientists and practitioners. paul revere was a member of the first local board of health in the united states (boston, 1799). the editors sign their posts "revere" to recognize the public service of a professional forerunner better known for other things.
