The North American Collaborative Study of Maternal Phenylketonuria. Status report 1993
R. Koch, H. L. Levy, R. Matalon, B. Rouse, W. Hanley and C. Azen
Division of Medical Genetics, Children's Hospital, Los Angeles, CA 90027.
Neonatal screening for phenylketonuria (PKU) has created an unexpected
problem as females with PKU are reaching childbearing age. Surveys have
revealed that maternal phenylalanine blood concentrations above 1200
mumol/L are associated with microcephaly, mental retardation, congenital
heart defects, and intrauterine growth retardation among their offspring.
It is estimated that as many as 3000 hyperphenylalaninemic females may be
at risk for producing these fetal abnormalities. To examine this problem,
the North American Maternal PKU Collaborative Study has been developed to
evaluate the efficacy of a phenylalanine-restricted diet in reducing fetal
morbidity. Preliminary findings indicate that phenylalanine restriction
should begin before conception for females with PKU planning a pregnancy.
Dietary control should maintain maternal blood phenylalanine levels between
120 and 360 mumol/L and should provide adequate energy, protein, vitamin,
and mineral intake. Pregnant hyperphenylalaninemic females who achieved
metabolic control after conception or by the 10th week of pregnancy had a
better offspring outcome than anticipated.
