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Maternal Phenylketonuria Collaborative Study (MPKUCS) offspring: facial anomalies, malformations, and early
1Children's Hospital, University of Texas Medical Branch, Galveston 77555-0319, USA.
Insights
Maternal phenylketonuria (PKU) management is crucial for preventing fetal damage. Dietary control of phenylalanine (Phe) levels below 360 mumol/liter before and during pregnancy significantly reduces risks of congenital abnormalities and developmental issues in offspring.
Area of Science:
- Medical Genetics
- Maternal-Fetal Medicine
- Metabolic Disorders
Background:
- Untreated maternal phenylketonuria (PKU) poses severe risks to fetal development, including microcephaly, intellectual disability, and congenital heart disease (CHD).
- The Maternal Phenylketonuria Collaborative Study (MPKUCS) investigated the impact of maternal phenylalanine (Phe) control during pregnancy.
Purpose of the Study:
- To determine the effectiveness of dietary Phe control in preventing fetal damage associated with untreated maternal PKU.
- To evaluate malformations and developmental outcomes in offspring exposed to varying maternal Phe levels.
Main Methods:
- A cohort of offspring from MPKUCS pregnancies was analyzed for malformations and neurological signs.
- Maternal Phe levels were categorized into groups (< or = 360, 361-600, 601-900, > 900 mumol/liter) during critical gestational periods (0-8 and 8-12 weeks) and overall pregnancy.
- Statistical analysis examined relationships between maternal Phe levels and specific adverse outcomes.
Main Results:
- Frequencies of congenital abnormalities significantly increased with higher maternal Phe levels.
- Elevated Phe levels correlated with increased risks of CHD, microcephaly, intrauterine and postnatal growth retardation, craniofacial abnormalities, and abnormal neurological signs.
- Maintaining Phe levels below 360 mumol/liter demonstrated a protective effect, with significantly lower rates of adverse outcomes compared to higher Phe levels.
Conclusions:
- Dietary management of PKU, achieving Phe levels below 360 mumol/liter prior to conception and throughout pregnancy, is essential for preventing fetal damage.
- Early and consistent Phe control is critical for mitigating risks of congenital malformations and developmental deficits in offspring of mothers with PKU.
Abstract:
Maternal phenylketonuria (PKU) in untreated women has resulted in offspring with microcephaly, mental retardation, congenital heart disease (CHD), and intrauterine growth retardation. The Maternal Phenylketonuria Collaborative Study (MPKUCS) was designed to determine the effect of dietary control of blood phenylalanine (Phe) during pregnancy in preventing damage to the fetus associated with untreated Maternal PKU. A cohort of offspring from MPKUS pregnancies was ascertained and examined to evaluate malformations, including CHD, craniofacial abnormalities, microcephaly, intrauterine and postnatal growth retardation, other major and minor defects, and early abnormal neurological signs. For analysis, the women were grouped according to their mean Phe levels in mumol/liter, < or = 360, 361-600, 601-900, or > 900, during critical gestational weeks of 0-8 (N = 203) and 8-12 (N = 190), and average for Phe exposure throughout pregnancy (N = 183). Frequencies of congenital abnormalities increased with increasing maternal Phe levels. Significant relationships included average Phe 0-8 weeks and CHD (P = 0.001); average Phe 8-12 weeks and brain, fetal, and postnatal growth retardation (P < 0.0005 for all), wide nasal bridge (P < 0.0005), and anteverted nares (P = 0.001); and average Phe exposure during the entire pregnancy and neurological signs (P < 0.0005). Although 14% of infants had CHD, none of the CHD occurred at 120-360 mumol/liter and only one (3%) at 361-600 mumol/liter. At levels of 120-360 mumol/liter, there were three infants (6%) with microcephaly, two (4%) with postnatal growth, and none with intrauterine growth retardation, in contrast to 85%, 51%, and 26%, respectively, with Phe above 900 mumol/liter. These data support the concept that women with PKU should begin a low-phenylalanine diet to achieve Phe levels of < 360 mumol/liter prior to conception and should maintain this throughout pregnancy.