Monday, November 06, 2006

Belated Halloween Edition

Porphyrias are a family of relatively rare diseases that present symptoms reminiscent of the characters immortalized by Lon Chaney, Jr. and Bela Lugosi. There's ample discussion in the literature about whether these diseases spawned the myths we recognize today. Porphyria sufferers may have anemia, light sensitivity, and reddish colored urine, or excessive hair growth. The underlying problem has to do with how the body makes and utilizes porphyrin, part of an oxygen-carrying complex in our blood. The molecular underpinnings of the disease are largely unknown, but a recent Nature letter presents evidence that some porphyrias may be due to a defect in a specific protein.
the ref: Nature 2006, 443, 586-589.
This protein, called ABCB6, transports porphyrins to a place where they can bind to iron. This iron-porphyrin combo eventually ends up in hemoglobin. This work points out that it isn't necessarily just the production of porphyrins that's the problem, that getting porphyrins where they need to be so that they can do their job is equally important.
This idea reminds me a little of the distinction between Type I and Type II diabetes. The underlying theme that diseases with the same symptoms could come from "manufacturing" or "distribution" issues must be more common than I realize.
Type I diabetes: decreased or no insulin production
Type II diabetes: insulin's around, but the body isn't responding to it properly
There was supposed to be a chemistry grad student with porphyria beginning in my year, 2002. The department spent a sizable chunk of change renovating an entryway so that she could turn off all lights when she needed to, and they built her a private office and everything. (I think she would've been a computational chemist). She deferred enrollment for a year and then never arrived. Not sure where she is today.



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