It also, if it's being shunted off into some other
pathways, it's producing metabolites that we are not accustomed to smelling.
So the musty odor of the sibling
pair with phenylketonuria wasn't a problem with hygiene.
It was that they're producing metabolic products at
levels that our noses aren't accustomed to smelling.
So they just smell different. So those
two symptoms were really a consequence of
phenylalanine being shunted off into some other pathway.
But what about the other?
The neurological complications, the hypopigmentation.
Well, if you look at this pathway, right?
If you're not converting phenylalanine to tyrosine, you have too little tyrosine.
And if you look down here, you'll see that
there are various neurotransmitter systems within the brain that are,
then are going to be deficient because you don't have enough tyrosine.
Probably the neurological complications are a
consequence of deficiency in this pathway.
And if you look down lower here, you see
melanocytes as a consequence of this pathway as well.
So the hypopigmentation, the eczema, is also
probably the consequence of the reduced tyrosine.