Steve,

 

I do understand what you are trying to get at. This topic came up a year or so ago when someone posted about a condition involving an enzyme deficiency that was "cured" when some parents hired a scientist to develop a synthetic form of that enzyme.  There was speculation on this mb at the time about why such a thing couldn’t also be done for CAH....in other words, why not just develop a synthetic form of 21-hydroxylase and take it via pill form (or something like that?)

 

At the time, I thought this was interesting, but figured there must be a reason why this had not been attempted for something like CAH, if it sounded like such an obvious solution.  Out of curiosity, I decided to look up the definition of "enzyme" in the medical dictionary, even though I thought I pretty much understood what it meant.  

 

Page 292 of Mosby’s Medical Encyclopedia gave this as the definition of an enzyme: "a protein that speeds up or causes chemical reactions in living matter.  Most enzymes are produced in tiny amounts and affect reactions that take place within the cells.  Digestive enzymes are produced in large amounts and act outside the cells in the digestive tube."

 

After reading that, I suspected that the difference between enzymes acting inside or outside of the cells was what determined whether you could simply supplement the missing enzyme.  I also suspected that the reason why this other condition was "curable" was because it involved a missing digestive enzyme, rather than an enzyme produced within the cells.  I don’t remember what that condition is called anymore, but did look it up on the web.  Sure enough, that was the case. 

 

I did also subsequently ask our peds endo about this.  He confirmed that my thinking about this was correct. 

 

So, to get back to your question about why you can’t do the same thing with the adrenal enzymes that you can do with digestive enzymes:  it’s because adrenal enzymes exist within the cells, while digestive enzymes exist outside the cells.  It may be possible to replace a digestive enzyme with an oral substitute, but we are probably still light years away from being able to do that with these other types of enzymes.

 

As an aside, CAH is not the only condition that involves a problem with a missing intracellular enzyme.....so, I believe, is Muscular Dystrophy.  I am sure there are many others.  Conditions such as Cystic Fibrosis and Sickle Cell Anemia also involve problems with enzyme processing within the cells.  I agree that it would be great if all these disorders could be fixed simply by popping a pill to fix the enzyme problem.  But--unfortunately---when you are talking about changing the inner workings of a cell---I don’t think doing that is anywhere near as easy as it sounds.