Cerebrospinal fluid neurotransmitter metabolites in neurologically normal infants and children

Significant inverse correlations with age were observed for free 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA) concentrations in CSF from 75 neurologically normal newborns, infants, and children aged 1 day to 10 years. The concentration of free MHPG decreased rapidly in early neonatal life and was reduced to near adult levels by 8 to 9 months of age. Adult levels of 5-HIAA were observed at about 4 years of age whereas HVA concentrations were still above adult levels at 10 years of age. Data from 0- to 1-month-old premature (28 to 32 weeks of gestation) and full-term (37 weeks of gestation) infants revealed marked changes in HVA and 5-HIAA concentrations which were related to postconceptional rather than postnatal age. This study demonstrates a previously undetected age effect on CSF MHPG concentration during the neonatal period and provides valuable normal data that are necessary for the interpretation of CSF monoamine metabolites in infants and children with hyperphenylalaninemia and other neurologic disease involving monoamine neurotransmitters.