We examined lipoproteins in phenylalanine hydroxylase deficiency during the first years of life.
At birth, decrease of high-density lipoprotein predominated over low-density lipoprotein.
At 3 and 12 months, decrease of low-density lipoprotein predominated over high-density lipoprotein.
The decreases of lipoproteins in phenylketonuria were greater than those in benign hyperphenylalaninemia.
Phenylalanine hydroxylase deficiency strongly influences on lipoproteins during early life.