Question
What are the clinical features of phenylketonuria?
Answer
The main clinical manifestations of phenylketonuria include skin and hair abnormalities, body odor changes, and growth delays. Infants with the condition may experience dry skin, frequent eczema, and skin scratch syndrome. Due to the inhibition of tyrosinase, melanin production increases, resulting in lighter hair color in the children, often brown. Moreover, as phenylalanine cannot be metabolized normally, it produces phenyl lactate and phenyl acetate, which are excreted through sweat and urine, leading to a musty or mouse-like odor. Typically, the severity of clinical manifestations is related to the type of PAH gene mutation, with clinical phenotypes associated with cofactor deficiency being less severe.