Yes, i agree the established view of genetics is a murky pond! I like to think that we have the ability to change our DNA...and i think if we are aware of which enzymes are not working so well, we can address these issues using nutrition mostly...sometimes bypassing the mutations, in other ways trying to help re-code the mutation.
It's early days yet, the field of nutrigenomics - and it'll be interesting to see if using an nutritional angle on enzymatic mutations helps to 're-write' the gene and correct it.
Bruce Lipton certainly advocates that we can change our DNA - or rather he observed that in different environments DNA changed. That's promising research :-)