Question
Recently, I have become aware of the seriousness of phenylketonuria. What methods can be used to screen for this condition?
Answer
Currently, high-performance liquid chromatography is used to detect the levels of neopterin and biopterin in urine to identify different types of PKU. In typical PKU patients, there is an increased total excretion of biopterins in urine, with a normal ratio of neopterin to biopterin. Children with DHPR defects also show an increase in total biopterin levels; 6-PTS defects are characterized by increased excretion and an abnormal ratio of neopterin to biopterin; and children with GTP-CH defects have elevated levels of neopterin.