Search

Pregnant women with phenylketonuria who eat a diet free of phenylalanine can substantially reduce the risk of damage to their baby. This was the conclusion of a 12-year follow-up of 576 women with phenylketonuria, a metabolic disease that can cause mental retardation.

Infants of mothers with phenylketonuria (PKU), an inborn error of metabolism, may develop microcephaly, an abnormal smallness of the head; mental retardation; and congenital heart defects. They also tend to have low birthweight. There is limited information about the development of abnormalities in children of fathers with PKU. One study showed that men with PKU had lower sperm counts and reduced semen volume, suggesting a limited reproductive potential. However, men with PKU are capable of fathering children, and these children have a lower frequency of abnormalities than children of mothers with PKU. Previous studies examining the outcome of children of fathers with PKU have produced inconsistent results. Six families of fathers with PKU are described and include nine offspring without PKU. The results suggest that paternal PKU does not adversely affect the outcome of offspring. None of the nine children had microcephaly, low birthweight, or congenital heart disease. In addition, the study showed that men with PKU have normal fertility. The greater frequency of abnormalities associated with maternal PKU may result from the transfer of biochemical abnormalities from the mother to the fetus during pregnancy, not from damage to the fertilized egg caused by genetic factors. (Consumer Summary produced by Reliance Medical Information, Inc.)

No 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 μmol/liter, ≤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 μmol/liter and only one (3%) at 361–600 μmol/liter. At levels of 120–360 μmol/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 μmol/liter. These data support the concept that women with PKU should begin a low-phenylalanine diet to achieve Phe levels of <360 μmol/liter prior to conception and should maintain this throughout pregnancy. Am. J. Med. Genet. 69:89–95, 1997. © 1997 Wiley-Liss, Inc.

No Abstract