In Taiwan, one in 34,000 infants are born with phenylketonuria, but provided they are given an appropriate diet during infancy, their prognosis is good and they are likely to attain a normal IQ.
以國內發生率約三萬四千分之一的苯酮尿症為例，若在新生兒期即給予適當的飲食控制，則預後良好，智商也可達正常人的標準。