Cross-cultural perspectives on coping with the risks of maternal phenylketonuria

Abstract

Maternal phenylketonuria (PKU) refers to the deleterious effects on a fetus due to high maternal phenylalanine levels. Prevention of these effects requires that women with PKU reduce their blood phenylalanine levels prior to and throughout pregnancy which means that they plan their regnancies and adhere to a phenylalanine restricted diet. According to a psycho-social model of maternal PKU, a first necessary step in preventing the effects of maternal PKU is prevention of unplanned pregnancies i.e.: using effective family planning practices. In the present study, findings are presented on seventy-five phenylketonuric women (60 from the United States and 15 from Israel) who participate in a prospective longitudinal study, to reveal the reasons why the proportion of pregnancies treated prior to conception has consistently been higher in Israel than in the United States. The two groups were interviewed and administered a battery of tests and questionnaires measuring a wide range of variables associated with family planning. Subjects in the United States were found to have more knowledge about fertility, contraception and maternal PKU. Israeli subjects held more negative attitudes towards and were less engaged in premarital sexual relationships, more frequently used oral contraceptives, had stronger motivation to have their own children, and perceived their disease to have a more negative effect on their lives. These findings suggest that the issues in maternal PKU are cultural as well as medical and psychosocial.     

Developmental Timing of Exposure to Elevated Levels of Phenylalanine Is Associated with ADHD Symptom Expression

This study addresses attention deficit hyperactivity disorder (ADHD), with a focus on how the timing of a known biological insult affects ADHD symptom expression. The sample consists of children exposed to elevated levels of phenylalanine, either postnatally as in Phenylketonuria (PKU; n = 46) or prenatally as in Maternal PKU (MPKU; n = 15). Non-hyperphenylalaninemic siblings of children with PKU (n = 18) serve as controls. Results indicate that elevated levels of phenylalanine are associated with ADHD symptoms. The manifestations of the symptom expression are dependent on exposure timing: prenatal exposure is associated with a higher likelihood of expressing hyperactive/impulsive symptoms and postnatal exposure is associated with a higher likelihood of expressing inattentive symptoms. This toxicity is dose-dependent and higher levels of phenylalanine appear more detrimental.     

Phenylketonuria in Children and Mothers: Genes, Environments, Behavior

ABSTRACT— Phenylketonuria (PKU) is an inborn metabolic error in which metabolism of phenylalanine into tyrosine is disrupted. If the diet of an infant with PKU is not restricted, blood phenylalanine levels are elevated, leading to irremediable brain damage and severe mental retardation. Children with PKU who are placed early and continuously on a low-phenylalanine diet develop normal levels of intelligence, and brain damage is largely prevented. However, if the diet of a mother with PKU is unrestricted during her pregnancy, high phenylalanine levels in her blood can cross the placental barrier and damage the developing fetus in multiple ways. These results demonstrate how genes and environmental factors combine to create prenatal environments that can have profound effects on the growth and development of offspring during infancy and childhood.