title: Maternal non-phenylketonuric mild hyperphenylalaninemia.
abstract: Unlike maternal phenylketonuria (PKU) which produces severe birth defects when untreated during pregnancy, maternal non-PKU mild hyperphenylalaninemia (MHP) has a less severe impact but whether it is benign or may have long-term consequences for offspring has been unclear. From an international survey of maternal MHP we obtained information about 86 mothers (blood phenylalanine (Phe) 150-720 mumol/l), their 219 untreated pregnancies and 173 offspring. Spontaneous fetal loss and congenital anomalies were no more frequent than normally expected. Median Z-scores for birth length and birth head circumference and offspring IQ (100), however, were significantly lower for maternal Phe > 400 mumol/l than for maternal Phe < 400 mumol/l, in which the median offspring IQ was 108. Data on maternal MHP from the prospective Maternal PKU Collaborative Study (MPKUCS) are as yet incomplete but seem to be conforming to the general pattern of the international survey. We conclude that maternal blood Phe levels above 400 mumol/l in maternal MHP are associated with lower birth measurements and slightly lower offspring IQ. It would seem that dietary intervention to lower the maternal Phe levels to below 400 mumol/l might be indicated in maternal MHP pregnancies with the higher blood Phe levels.
authors.affiliation: Children's Hospital, Boston, MA 02115, USA.
authors.forename: H L
authors.initials: HL
authors.lastname: Levy
authors.forename: S E
authors.initials: SE
authors.lastname: Waisbren
authors.forename: D
authors.initials: D
authors.lastname: Lobbregt
authors.forename: E
authors.initials: E
authors.lastname: Allred
authors.forename: A
authors.initials: A
authors.lastname: Leviton
authors.forename: R
authors.initials: R
authors.lastname: Koch
authors.forename: W B
authors.initials: WB
authors.lastname: Hanley
authors.forename: B
authors.initials: B
authors.lastname: Rouse
authors.forename: R
authors.initials: R
authors.lastname: Matalon
authors.forename: F
authors.initials: F
authors.lastname: de la Cruz
mesh_terms: D000328:Adult; D000592:Amino Acid Metabolism, Inborn Errors / Q000097:blood; D001724:Birth Weight; D005260:Female; D006257:Head / Q000033:anatomy & histology; D006801:Humans; D007231:Infant, Newborn; D007360:Intelligence; D010651:Phenylalanine Hydroxylase / Q000172:deficiency*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood; D011256:Pregnancy Outcome; D011297:Prenatal Exposure Delayed Effects
chemical_list: D010651:Phenylalanine Hydroxylase