Maternal phenylketonuria

Maternal phenylketonuria--the Irish experience

The outcome of 48 pregnancies in 18 women with elevated phenylalanine was studied. The women were divided into two groups, diet and non-diet. All the women on diet had severe hyperphenylalaninaemia and only six were on the amino acid mixture at conception. In the non-diet group four women had concentrations of less than 1000 mumols/L and five had severe hyperphenylalaninaemia. Three deaths and one stillbirth occurred in the non-diet group. Microcephaly occurred in 24 children; 11 in the diet group and 13 in the non-diet group. There were five miscarriages in the non-diet group and one in the diet group. Diet is beneficial when started early but planned pregnancies, good motivation and compliance were difficult to achieve in this group of women despite every reasonable effort by the PKU clinic.

Maternal phenylketonuria-chronology of the detrimental effects on embryogenesis and fetal development: pathological report, survey, clinical application

Maternal phenylketonuria (PKU) is likely to have detrimental effects on embryogenesis and fetal development. Manifestations in the offspring include spontaneous abortion, various congenital malformations, intrauterine growth retardation, and microcephaly. The time at which the metabolic abnormalities induce pathologic embryogenesis can be documented by knowing the time of the development of specifically damaged organ systems. This review reveals that, while the most recognized congenital malformations occur in the heart, the most common abnormality is growth inhibition occurring throughout pregnancy. The organ system most commonly affected by this growth inhibition is the brain, resulting in a high incidence of micrencephaly. It appears that maternal phenylketonuria interferes with appropriate fetal growth and that this effect occurs during the entire course of pregnancy and has no tissue specificity. This information can be both informative to pathologists and useful to clinicians.

Maternal phenylketonuria--results of dietary therapy

Untreated maternal phenylketonuria (PKU) may result in nonphenylketonuric offspring with mental retardation, microcephaly, congenital heart disease, and low birth weight. We obtained information about 34 pregnancies in which dietary therapy was instituted to lower the concentration of phenylalanine in maternal blood in an attempt to avoid fetal damage. The outcomes varied from mental normality with no evidence of fetal effect to neonatal death due to congenital heart disease. Dietary therapy with control of the maternal biochemical abnormalities is not yet of proved efficacy in preventing these fetal effects. The available data tend to support initiation of dietary therapy prior to conception for best results, but the number of cases is small and points to the need for further research.