The first study of successful pregnancies in Chinese patients with Phenylketonuria.

BACKGROUND: Since the inception of newborn screening programs in China in the 1990s, pregnancy among patients with inherited, metabolic disorders has become more common. This study explores the management and outcomes of planned, full-term pregnancies in patients with phenylketonuria (PKU). METHOD: Married patients with PKU from 2012 to 2017 were enrolled to receive prenatal counseling and regular health assessments. Study-related assessments included the timing of Phe-restricted diets, maternal weight gain, gestational age, pregnancy complications, and blood Phe concentrations (both pre-conception and during pregnancy), obstetrical data, and offspring outcomes(e.g. anthropomorphic measurements and developmental quotients [DQs]). RESULTS: A total of six offspring were successfully delivered. The mean ± SD (range) age of the mother at delivery was 26.3 ± 4.7 (range: 21.1-32.5) years. The mean duration of Phe control before pregnancy was 5.5 ± 1.3(range: 3.1-6.5) months. During pregnancy, the proportion of blood Phe concentrations within the clinically-recommended target range (120-360 µmol/L) ranged from 63.2-83.5%. Low birth weight (< 2500 g) offspring occurred in two women who experienced suboptimal metabolic control. In addition, offspring DQ was related to the proportion of blood Phe levels per trimester that were within the recommended range (r = 0.886, p = 0.016). CONCLUSION: This is the first report of women in China with PKU who successfully gave birth to clinically healthy babies. Infant outcomes were related to maternal blood Phe management prior to and during pregnancy. In maternal PKU patients with poor compliance to dietary treatment, sapropterin dihydrochloride (6R-BH4) may be an option to improve the management of blood Phe levels.

Management of Women With Phenylalanine Hydroxylase Deficiency (Phenylketonuria): ACOG Committee Opinion Summary, Number 802.

Phenylalanine hydroxylase (PAH) deficiency is an autosomal recessive disorder of phenylalanine metabolism that is characterized by insufficient activity of PAH, a hepatic enzyme. Throughout this document, PAH deficiency is used instead of the older nomenclature of phenylketonuria, in order to reflect the spectrum of PAH deficiency and in accordance with the terminology established by the American College of Medical Genetics and Genomics. Aspects of PAH deficiency management that are particularly relevant to obstetrician-gynecologists or other obstetric care providers include the prevention of embryopathy associated with maternal hyperphenylalaninemia and PAH deficiency and the risk of genetic transmission of PAH deficiency. Family planning and prepregnancy counseling are recommended for all reproductive-aged women with PAH deficiency. The fetal brain and heart are particularly vulnerable to high maternal concentrations of phenylalanine. The crucial role played by maternal dietary restriction before and during pregnancy should be stressed in counseling patients with PAH deficiency; the goal should be to normalize blood phenylalanine levels (less than 6 mg/dL) for at least 3 months before becoming pregnant and to maintain at 2-6 mg/dL during pregnancy, in order to optimize developmental outcomes for the fetus. Although phenylalanine levels are increased in the breast milk of patients with PAH deficiency, breastfed infants who do not have PAH deficiency have normal enzyme levels and no dietary restriction. Breastfeeding is safe for infants born to women who have PAH deficiency provided the infants do not have PAH deficiency. Coordinated medical and nutritional care, as well as follow-up with the patient's metabolic geneticist or specialist, are important in the postpartum period. Because newborns with PAH deficiency appear normal at birth and early detection can improve developmental outcomes for children, newborn screening for PAH deficiency is mandated in all states. This Committee Opinion has been revised to include updates on advances in the understanding and management of women with PAH deficiency and recommendations on prepregnancy counseling, serial fetal growth assessments, and fetal echocardiography.

Management of Women With Phenylalanine Hydroxylase Deficiency (Phenylketonuria): ACOG Committee Opinion, Number 802.

Phenylalanine hydroxylase (PAH) deficiency is an autosomal recessive disorder of phenylalanine metabolism that is characterized by insufficient activity of PAH, a hepatic enzyme. Throughout this document, PAH deficiency is used instead of the older nomenclature of phenylketonuria, in order to reflect the spectrum of PAH deficiency and in accordance with the terminology established by the American College of Medical Genetics and Genomics. Aspects of PAH deficiency management that are particularly relevant to obstetrician-gynecologists or other obstetric care providers include the prevention of embryopathy associated with maternal hyperphenylalaninemia and PAH deficiency and the risk of genetic transmission of PAH deficiency. Family planning and prepregnancy counseling are recommended for all reproductive-aged women with PAH deficiency. The fetal brain and heart are particularly vulnerable to high maternal concentrations of phenylalanine. The crucial role played by maternal dietary restriction before and during pregnancy should be stressed in counseling patients with PAH deficiency; the goal should be to normalize blood phenylalanine levels (less than 6 mg/dL) for at least 3 months before becoming pregnant and to maintain at 2-6 mg/dL during pregnancy, in order to optimize developmental outcomes for the fetus. Although phenylalanine levels are increased in the breast milk of patients with PAH deficiency, breastfed infants who do not have PAH deficiency have normal enzyme levels and no dietary restriction. Breastfeeding is safe for infants born to women who have PAH deficiency provided the infants do not have PAH deficiency. Coordinated medical and nutritional care, as well as follow-up with the patient's metabolic geneticist or specialist, are important in the postpartum period. Because newborns with PAH deficiency appear normal at birth and early detection can improve developmental outcomes for children, newborn screening for PAH deficiency is mandated in all states. This Committee Opinion has been revised to include updates on advances in the understanding and management of women with PAH deficiency and recommendations on prepregnancy counseling, serial fetal growth assessments, and fetal echocardiography.

Phenylalanine and tyrosine measurements across gestation by tandem mass spectrometer on dried blood spot cards from normal pregnant women.

PURPOSE: Maternal phenylketonuria (MPKU) requires strict control of phenylalanine (Phe) and supplemental tyrosine (Tyr). Monitoring during pregnancy using dried blood spot (DBS) cards by tandem mass spectrometry (MS/MS) is now standard practice, however there are no Phe and Tyr reference ranges for DBS MS/MS method in healthy pregnant women. METHODS: DBS cards (63-1364 days in storage) from healthy women with singleton pregnancies were analyzed by MS/MS. Three hundred ninety DBS cards from 170 pregnancies (5/1-39/6 weeks' gestation), were tested. RESULTS: Both Phe and Tyr levels declined from the first trimester (Phe: 36.2 +/- 10.6; Tyr 25.7 +/- 9.7 µmol/L) to the second trimester (Phe 33.4+/-9.3; Tyr 21.7+/- 6.7 µmol/L) and remained stable in the third trimester (Phe 32.3 +/- 8.7; Tyr 21.0 +/- 6.6 µmol/L). Phe and Tyr levels declined over time since collection (Phe: 0.004 µmol/L per day; Tyr 0.002 µmol/L). Nomograms by gestational age were created using raw data and data adjusted for time from sample collection. Reference ranges by trimester are provided. CONCLUSIONS: Both Phe and Tyr decline quickly during the first trimester and remain relatively constant over the second and third trimesters. These nomograms will provide a valuable resource for care of MPKU.

[Singleton and twin pregnancies of PKU patients - individual variability of phenylalanine tolerance: experience of a single treatment center (Preliminary report)].

Phenylketonuria (PKU) is the autosomal recessive deficiency of phenylalanine hydroxylase resulting in the accumulation of phenylalanine (Phe) in blood and in the brain. Phe restriction in a patient's diet is determined depending on the amount of Phe intake which allows for stable blood Phe levels within the therapeutic range of 120-360µmol/L. In clinical practice the empirical determination of Phe tolerance relies on frequent assessment of blood Phe concentrations in relation to Phe intake from food records. Untreated maternal PKU may lead to maternal PKU syndrome in offspring. The objective of the study was to compare Phe tolerance during the course of singleton and multiple pregnancies of PKU patients. Case subjects and methods: The cases reviewed included three sets of classical PKU-affected Polish women on a low-phenylalanine diet during the course of singleton and twin pregnancies and their PKU-unaffected newborns. All the patients were under regular supervision of a metabolic dietitian to stabilize blood Phe levels and determine Phe tolerance. Data on pregnancy weight gain, the gestational age when the diet initiated, the percent of Phe assessments < 120 µmol/L and > 360 µmol/L, as well as offspring birth measurements were analyzed. RESULTS: The total increase in Phe tolerance and its pattern during the course of singleton and twin pregnancies differed remarkably in each patient. Three PKU women (Q383X/R408W, EX3DEL/EX3DEL, R281L/R408W) increased their Phe tolerance in singleton and twin pregnancies by 579%/468%, 674%/261%, and 427%/236%, respectively. During the last 10 weeks of singleton and twin pregnancy Phe tolerance showed an increase by 62%/149%, 33%/64%, and 37%/40%, respectively. The analysis of predictors for Phe tolerance showed that an individual's weight gain and the fetal weight gain as estimated from liveborn birth-weight data had no predictive capacity. CONCLUSIONS: Individual Phe tolerance in singleton pregnancies of PKU patients does not predict tolerance in twin pregnancy. Further research on the growing population of multiple pregnancy PKU patients is necessary to provide evidence-based guidelines to optimize the treatment of PKU in females of childbearing age.

Ten years of specialized adult care for phenylketonuria - a single-centre experience.

BACKGROUND: Specialized adult care of phenylketonuria (PKU) patients is of increasing importance. Adult outpatient clinics for inherited errors of metabolism can help to achieve this task, but experience is limited. Ten years after establishment of a coordinated transition process and specialised adult care for inherited metabolic diseases, adult PKU care was evaluated with respect to metabolic control, therapy satisfaction, life satisfaction, sociodemographic data, economical welfare as well as pregnancy outcome. METHODS: All PKU patients transferred from paediatric to adult care between 2005 and 2015 were identified. A retrospective data analysis and a cross-sectional survey in a sub-cohort of 30 patients including a questionnaire for assessing quality of life (FLZm) were performed as a single-centre investigation at the metabolic department of the University Hospital Leipzig, Germany. For statistical analysis, Mann-Whitney-U-test, t-test for independent samples, ANOVA and chi square test were used as appropriate. RESULTS: 96 PKU patients (56 females/40 males; median age 32 years, range 18-62) were included. In the last 3-year period, 81% of the transferred patients still kept contact to the adult care centre. Metabolic control was stable over the evaluation period and dried blood phenylalanine concentrations mostly remained within the therapeutic range (median 673.0 µmol/l, range 213.0-1381.1). Sociodemographic data, economical welfare and life satisfaction data were comparable to data from the general population. However, differences could be revealed when splitting the cohort according to time of diagnosis and to management during childhood. 83% of the PKU adults were satisfied with the transition process and current adult care. 25 completed pregnancies were supervised; three newborns, born after unplanned pregnancy, showed characteristic symptoms of maternal PKU syndrome. CONCLUSIONS: Continuous care for adult PKU patients in a specialized outpatient clinic is successful, leading to good to satisfactory metabolic control and social outcomes. Uninterrupted good metabolic treatment throughout childhood and adolescence positively influences educational, professional and economic success in later life. Further effort in specialized paediatric and adult metabolic care is needed to prevent loss of follow-up and to support the recommended life-long treatment and/or care.

Medical Problems in Obstetrics: Inherited Metabolic Disease.

An increasing number of women with rare inherited disorders of metabolism are becoming pregnant. Although, in general, outcomes for women and their children are good, there are a number of issues that need to be considered. Currently, limited specific guidance on the management of these conditions in pregnancy is available. Prepregnancy counselling with information on inheritance, options for reproduction, teratogenicity risk, potential impact on maternal health and long-term health of children should be offered. With appropriate specialist management, the teratogenic risk of conditions such as maternal phenylketonuria (PKU) can be eliminated, and the risk of metabolic decompensation in disorders of energy metabolism or intoxication significantly reduced. Multidisciplinary management, and close liaison between obstetricians and other specialists, is required for those women in whom there is cardiac, renal, respiratory, joint or other organ involvement.

[Maternal phenylketonuria]. / Maternális phenylketonuria.

Elevated maternal phenylalanine levels during pregnancy are teratogenic, and may result in embryo-foetopathy, which could lead to stillbirth, significant psychomotor handicaps and birth defects. This foetal damage is known as maternal phenylketonuria. Women of childbearing age with all forms of phenylketonuria, including mild variants such as hyperphenylalaninaemia, should receive detailed counselling regarding their risks for adverse foetal effects, optimally before contemplating pregnancy. The most assured way to prevent maternal phenylketonuria is to maintain the maternal phenylalanine levels within the optimal range already before conception and throughout the whole pregnancy. Authors review the comprehensive programme for prevention of maternal phenylketonuria at the Metabolic Center of Budapest, they survey the practical approach of the continuous maternal metabolic control and delineate the outcome of pregnancies of mothers with phenylketonuria from the introduction of newborn screening until most recently.

Tetralogy of Fallot variant with pulmonary atresia (pseudotruncus arteriosus) in a case of maternal PKU syndrome.

The authors report on a child with a rare variant of the Tetralogy of Fallot with pulmonary atresia also known as Pseudotruncus arteriosus, who was born by a mother affected by classic phenylketonuria (PKU), diet free of phenylalanine until the age of seven years. According to the authors, this is the first example of such rare variant in an offspring of maternal PKU syndrome.

Maternal phenylketonuria: low phenylalaninemia might increase the risk of intra uterine growth retardation.

BACKGROUND: Malformations and mental retardation in the offspring of women with Phenylketonuria (PKU) can be prevented by maintaining maternal blood Phenylalanine (PHE) within a target range (120-300 µmol/L) through a PHE-restricted diet. In a former French study, a high and unexpected proportion of intra uterine growth retardation (IUGR) has been reported. Guidelines have been proposed to all French centres caring for maternal PKU since 2002. OBJECTIVE: To confirm IUGR and investigate its causes. The other goals were to assess the follow-up of these pregnancies based on the new guidelines and the pertinence of these recommendations. DESIGN: Clinical, biological and ultrasound data of all pregnancies in PKU women in France, from 2002 to 2007 were retrospectively analyzed. RESULTS: Data from 115 pregnancies in 86 women with PKU were collected. Ninety percent of women had been informed of the risk of maternal PKU in the absence of a strict diet during pregnancy, 88 % of women had started a diet before conception, and 45 % of infants were born small for gestational age (birth length and/or weight ≤-2 SD). PHE intakes were lower in the group with IUGR from the fifth to the eighth month of pregnancy and duration of time spent at <120 µmol/L during pregnancy was associated with a higher risk of IUGR. CONCLUSION: Hyperphenylalaninemia (HPA) is not the only risk factor for IUGR; PHE lower than 120 µmol/L could also be associated with the IUGR occurrence. Even if the monitoring of these pregnancies has been improved since the initiation of guidelines, we would like to stress on the importance of the dietary aspect of the disease.

Maternal phenylketonuria and hyperphenylalaninemia in pregnancy: pregnancy complications and neonatal sequelae in untreated and treated pregnancies.

BACKGROUND: Untreated maternal phenylketonuria or hyperphenylalaninemia may result in nonphenylketonuric offspring with neonatal sequelae, especially intellectual disability, microcephaly, and congenital heart disease (CHD). Dietary treatment to control phenylalanine concentrations can prevent these sequelae. OBJECTIVE: We aimed to present an overview of reported pregnancy complications and neonatal sequelae of maternal phenylketonuria or hyperphenylalaninemia in untreated and treated pregnancies. DESIGN: A MEDLINE and EMBASE search was conducted for case reports and case series that assessed maternal phenylketonuria or hyperphenylalaninemia during pregnancy. Pregnancy complications (spontaneous abortion, intrauterine-fetal-death, and preterm delivery) and neonatal sequelae [small for gestational age (SGA), microcephaly, CHD, intellectual or developmental disabilities (IDDs), and facial dysmorphism (FD)] were analyzed. Fifteen unpublished pregnancies from our clinic were added. RESULTS: We retrieved 196 pregnancies, of which 126 pregnancies were untreated and 70 pregnancies were treated. The occurrence of pregnancy complications was not significantly different between untreated and treated pregnancies. Except for SGA, all neonatal sequelae were more frequent in untreated pregnancies. Moreover, the occurrence of SGA, microcephaly, and IDDs was significantly related to the mean phenylalanine concentration in each trimester, whereas the occurrence of FD was related only to the first trimester. CONCLUSIONS: We present the largest cohort of untreated pregnant women with phenylketonuria or hyperphenylalaninemia since 1980. The results follow the general pattern reported by other researchers. We underline that the treatment of pregnant women with phenylketonuria or hyperphenylalaninemia is of great importance to prevent neonatal sequelae. We strongly recommend starting treatment before conception because we showed the deleterious effect of an increased mean first-trimester phenylalanine concentration on FD.

Maternal phenylketonuria.

The maternal phenylketonuria (MPKU) syndrome is an example of biochemical teratogenesis caused by high phenylalanine concentrations in serum of a pregnant woman (over 360 micromol/L). Active transport through the placenta increases 1.5-fold the phenylalanine level in the child's blood as compared to concentrations recorded in the mother. Increased phenylalanine concentrations may lead to disorders in proliferation of neural cells, neuronal migrations and affect the process of synaptogenesis and myelination. The authors present two children with maternal phenylketonuria with a characteristic clinical picture. Particular attention was drawn to the fact of diagnosed phenylketonuria in mothers following a suspicion and diagnosis of maternal phenylketonuria in children, as well as the occurrence of refractory epilepsy in one of the patients. The mothers' average phenylalanine concentration exceeded the value of 1300 micromol/L, while in children it ranged between 117-160 micromol/L.

Neuropathology of a 4-month-old infant born to a woman with phenylketonuria.

We evaluated the brain of a 4-month-old male infant whose mother had inadequately controlled maternal phenylketonuria (MPKU). At autopsy his brain was normally developed but underweight. We found ventriculomegaly, hypoplastic cerebral white matter, and delay of myelination in late myelinating tracts without white matter astrocytosis and without chronic lesions in any gray matter structure. We compared the development of the infant's white matter tracts with published data on infant myelination. Congenital heart disease complicated the case. Abnormalities in developmental white matter may account for neurological abnormalities in infants with MPKU.

Tetrahydrobiopterin and maternal PKU.

A 29-year-old woman with PKU is presented, who was successfully treated with phenylalanine restriction as well as oral BH4 during this pregnancy, with a normal outcome. Her PAH mutation was R408W/F39L. Remarkably, the blood phenylalanine control was easily accomplished during this pregnancy. The lack of nausea and vomiting during the first trimester suggests that the occurrence of CHD in babies born to women with PKU may be reduced with BH4.

An exceptional Albanian family with seven children presenting with dysmorphic features and mental retardation: maternal phenylketonuria.

BACKGROUND: Phenylketonuria is an inborn error of amino acid metabolism which can cause severe damage to the patient or, in the case of maternal phenylketonuria, to the foetus. The maternal phenylketonuria syndrome is caused by high blood phenylalanine concentrations during pregnancy and presents with serious foetal anomalies, especially congenital heart disease, microcephaly and mental retardation. CASE PRESENTATION: We report on an affected Albanian woman and her seven children. The mother is affected by phenylketonuria and is a compound heterozygote for two pathogenetic mutations, L48S and P281L. The diagnosis was only made in the context of her children, all of whom have at least one severe organic malformation. The first child, 17 years old, has a double-chambered right ventricle, vertebral malformations and epilepsy. She is also mentally retarded, microcephalic, exhibits facial dysmorphies and small stature. The second child, a girl 15 years of age, has severe mental retardation with microcephaly, small stature and various dysmorphic features. The next sibling, a boy, died of tetralogy of Fallot at the age of three months. He also had multiple vertebral and rib malformations. The subsequent girl, now eleven years old, has mental retardation, microcephaly and epilepsy along with facial dysmorphy, partial deafness and short stature. The eight-year-old child is slightly mentally retarded and microcephalic. A five-year-old boy was a premature, dystrophic baby and exhibits mental retardation, dysmorphic facial features, brachydactyly and clinodactyly of the fifth finger on both hands. Following a miscarriage, our index case, the youngest child at two years of age, is microcephalic and mentally retarded and shows minor facial anomalies. All children exhibit features of phenylalanine embryopathy caused by maternal phenylketonuria because the mother had not been diagnosed earlier and, therefore, never received any diet. CONCLUSION: This is the largest family suffering from maternal phenylketonuria reported in the literature. Maternal phenylketonuria remains a challenge, especially in woman from countries without a neonatal screening program. Therefore, it is mandatory to be alert for the possibility of maternal phenylketonuria syndrome in case of a child with the clinical features described here to prevent foetal damage in subsequent siblings.

Maternal phenylketonuria: report from the United Kingdom Registry 1978-97.

BACKGROUND: The effects of maternal phenylalanine on the fetus include facial dysmorphism, microcephaly, intrauterine growth retardation, developmental delay, and congenital heart disease. AIMS: To evaluate the impact of phenylalanine restricted diet in pregnant women with phenylketonuria (PKU) on their offspring. METHODS: Data on virtually all pregnancies of women with PKU in the United Kingdom between 1978 and 1997 were reported to the United Kingdom PKU Registry. The effect of the use and timing in relation to pregnancy of a phenylalanine restricted diet on birth weight, birth head circumference, the presence or absence of congenital heart disease (CHD), 4 year developmental quotient, and 8 year intelligence quotient were examined. RESULTS: A total of 228 pregnancies resulted in live births (seven twin pregnancies were excluded). In 110 (50%), diet started before conception. For this group mean (SD) birth weight was 3160 (612) g, birth head circumference 33.6 (1.9) cm, 4 year DQ 108.9 (13.2), 8 year IQ 103.4 (15.6), and incidence of CHD was 2.4%. In comparison, for those born where treatment was started during pregnancy (n = 91), birth weight was 2818 (711) g, birth head circumference 32.7 (2.0) cm, 4 year DQ 96.8 (15.0), 8 year IQ 86.5 (13.0), and incidence of CHD was 17%. Month-by-month regression analyses suggested that metabolic control by 12-16 weeks gestation had most influence on outcome. CONCLUSIONS: Many features of the maternal PKU syndrome are preventable by starting a phenylalanine restricted diet. Women with PKU and their carers must be aware of the risks and should start the diet before conception, or as soon after as possible.

Learning and behavioural difficulties but not microcephaly in three brothers resulting from undiagnosed maternal phenylketonuria.

Universal screening introduced in the 1960s has reduced the incidence of learning disability resulting from phenylketonuria (PKU), which is a treatable condition. Nonetheless, PKU may still be having an impact on the paediatric-age population. We report a woman with previously undiagnosed PKU who was born before the onset of universal screening. She is of normal intelligence, and so the diagnosis was not suspected until after the birth of her three children. Her serum phenylalanine concentration was found to be in excess of 1 mmol/L, well into the toxic range. She has had three sons, all of whom have a significant degree of learning disability resulting from intrauterine exposure to toxic levels of phenylalanine. None of the sons had microcephaly, a physical sign that, if present, might have helped to point towards the correct diagnosis. We suggest that maternal PKU should be suspected where there is sibling recurrence of cognitive impairment, particularly where the mother was born before the initiation of the neonatal screening programme for PKU.

The Maternal Phenylketonuria International Study: 1984-2002.

OBJECTIVE: The purpose of this report is to review the obstetric medical, psychological, and nutritional aspects and outcome of the women and offspring enrolled in the Maternal Phenylketonuria Study, which was established to assess the efficacy of a phenylalanine (Phe)-restricted diet in preventing the morbidity associated with this disorder. METHODS: A total of 382 women with hyperphenylalaninemia (HPA) were enrolled in the study and completed 572 pregnancies. Outcome measures were analyzed with chi2, Fisher exact text, analysis of variance, t test, Wilcoxon nonparametric test, and multiple logistic regression. Outcome measures were stratified according to maternal HPA classification and the time when dietary control was achieved. RESULTS: Optimal birth outcomes occurred when maternal blood Phe levels between 120 and 360 micromol/L were achieved by 8 to 10 weeks of gestation and maintained throughout pregnancy (trimester averages of 600 micromol/L). Mothers with mild HPA achieved similar birth outcomes as mothers who were in control preconceptually and those in control by 8 to 10 weeks of pregnancy. CONCLUSIONS: Before conception, counseling and early entrance into a prenatal care program is essential in achieving optimal fetal outcome in women with HPA. The achievement of pre- and periconceptional dietary control with a Phe-restricted diet significantly decreased morbidity in the offspring of women with HPA.

Role of nutrition in pregnancy with phenylketonuria and birth defects.

OBJECTIVE: The maternal phenylketonuria (PKU) syndrome is caused by high blood phenylalanine (Phe) levels during pregnancy, leading to a host of birth defects, especially microcephaly and congenital heart disease (CHD). For finding whether the maternal PKU syndrome could be prevented, an international collaborative study was organized to evaluate treatment with a Phe-restricted diet. Blood Phe levels, maternal weight gain, and nutrient intakes during pregnancy were evaluated as to their effect on the rate of microcephaly and CHD in the offspring. METHODS: The study was a prospective, longitudinal effort aimed at lowering blood Phe during pregnancy. Women were enrolled at time of referral for pregnancy. Nutrient intake analysis, which serves as the basis for this report, was available from 251 pregnancies. Subjects were stratified by blood Phe control of < or =600 micromol/L by 8 weeks gestation or >600 micromol/L by 8 weeks gestation. Outcome of these pregnancies was correlated to blood Phe levels, weight gain, and nutrient intake. RESULTS: The study goal was to attain blood Phe levels of 120 to 360 micromol/L 3 months preconception; however, this goal was achieved by only a limited number of patients. Therefore, the data presented were based on blood Phe control < or =600 micromol/L or >600 micromol/L by 8 weeks of gestation. Blood Phe control of < or =600 micromol/L by 8 weeks of gestation was attained by 86 (34.3%) of the 251 women in this study, whereas the other 165 women had blood Phe control >600 micromol/L by 8 weeks of gestation. Of the 251 offspring, 166 were born with normal head circumference and 85 were born with microcephaly (<2 standard deviations below normal). Women with blood Phe >600 micromol/L at 8 weeks of gestation included 78 (92%) of the 85 infants with microcephaly compared with 8% in the group of women who had blood Phe levels < or =600 micromol/L. Weight gain during pregnancy was related to the rate of microcephaly. The highest occurrence of microcephaly (58%) was found in the pregnant women who gained <70% of recommended weight gain. Stepwise logistic regression analysis was used to determine factors associated with microcephaly. Significant factors included higher blood Phe levels when off diet, higher average Phe exposure during the pregnancy, low prepregnancy weight, poor weight gain during the pregnancy, and lower intake of protein and higher iron intake during the pregnancy. Infants with CHD were found only in the group of women who had blood Phe levels >600 micromol/L by 8 weeks of gestation. There was a higher rate of CHD in the offspring who were born to women who consumed <50% of the recommended intake of protein in the first trimester. The main source of protein for women with PKU is the medical food; therefore, when protein intake was low, vitamin and mineral intakes were also inadequate. CONCLUSIONS: The data indicate that blood Phe control and how soon it is attained during pregnancy with PKU is important. Normal pregnancy weight gain should be encouraged to reduce microcephaly. Adequate protein and vitamin intakes early in pregnancy may have a protective effect for the prevention of CHD, even if blood Phe is elevated. The rate of microcephaly and CHD may be reduced if nutrient intake is optimal while attempting to control blood Phe levels.

Cognitive and behavioral development in maternal phenylketonuria offspring.

OBJECTIVE: To assess cognitive and behavioral outcome in treated maternal phenylketonuria (PKU) offspring. METHODS: In this prospective, longitudinal study, 228 children who were born to mothers with treated PKU or untreated mild hyperphenylalaninemia were compared with 70 control subjects at 7 years of age. RESULTS: Offspring cognitive outcome negatively correlated with the number of gestational weeks that elapsed until maternal metabolic control was achieved (r = -0.61). Behavioral outcome was similarly affected. Postnatal measurement of stimulation in the home was also related to offspring IQ. CONCLUSIONS: Children who are born to mothers who have PKU and attain metabolic control before or very early in pregnancy seem to begin life with undiminished potential. Delay in attainment of maternal metabolic control is associated with declines in offspring developmental outcome. The postnatal environment also significantly affects outcome. Interventions to improve dietary compliance before and throughout pregnancy as well as interventions to improve the postnatal home environment may reduce the risks associated with maternal PKU.