Shawn Christ, PhD, of the department of psychological sciences at the University of Missouri discusses how neurochemistry of the phenylketonuria (PKU) brain likely plays a role in the psychosocial changes seen in PKU patients not adhering to treatment.
This interview was made possible by a sponsorship from BioMarin Pharmaceutical Inc. Rare Disease Report has sole control over the editorial content.
One of the theories behind the increased rate of anxiety and depression that we see in some individuals with PKU is that it might be related to the impact that PKU has on serotonin.
I go back to some of the older animal studies. They would raise these animals with PKU and then sacrifice them and look at the levels in the brain of dopamine and serotonin. And the study I have in mind they actually saw bigger decreases in serotonin and dopamine.
And when we think about things like anxiety and depression – serotonin is the neurotransmitter that we think of as modulating that. And its consistent with this idea that in a general population, one of the major treatments for depression are SSRIs (selective serotonin reuptake inhibitors).
it's very theoretical – we haven't crossed those t’s and dotted those i’s, nor directly linked it but that's the idea.
So if we bring phenylalinine down, that decreases the competition between the phenylalanine and the tryptophan to get into the brain and now can improve the levels of serotonin because there's nothing inherently wrong with the tryptophan to serotonin system in PKU, its just that phenylalanine is disrupting system.