Anyone here understand genetic tests?

Cytochromes P450 (CYPs) are a family of enzymes that are primarily involved in the metabolism and clearance of chemical compounds, such as drugs, in the liver. There are a fairly large number of these enzymes, but only a handful of them are significant players in the metabolism of drugs. In principle, if one of your CYPs has a "poor metabolizer phenotype", and you take a drug that happens to be metabolized primarily by that specific CYP, you will need less drug to achieve the same effect and/or you might develop side effects at lower doses than people who are normal metabolizers (because you will not be able to metabolize/eliminate the drug as effectively as normal metabolizers). That being said, CYP345 is NOT one of the key CYPs, and I am only aware of one drug that is primarily metabolized by CYP345 - Eliglustat, a drug used to treat Gaucher disease. I think your doctor is right and this is not something to be concerned about.