Patient's question:
My nephew was diagnosed with phenylketonuria right after birth. The child is very frail, and the doctor said many things are not allowed to eat. The child has been consuming special formula milk. The child is growing particularly small and looks nothing like a child of that age. I feel extremely heartbroken seeing this. What kind of help is needed: What are the clinical diagnostic features of phenylketonuria?Doctor's answer:
Phenylketonuria primarily presents with the following clinical manifestations:1. Skin and hair manifestations: The skin is often dry and prone to eczema and skin scratch marks. Due to the inhibition of tyrosinase, melanin production increases, resulting in lighter-colored, brownish hair in affected children.
2. Other: Due to the lack of phenylalanine hydroxylase, phenylalanine is continuously converted into phenylpyruvate and phenylacetic acid through an alternative pathway, which are excreted in sweat and urine, giving a musty (or mouse-like) odor. Generally, clinical manifestations are related to the type of PAH gene mutation and the severity of the clinical diagnostic phenotype. A deficiency in cofactors tends to result in a milder clinical diagnostic phenotype compared to abnormal PAH protein.