Gestational carrier — A reproductive haven for offspring of mothers with phenylketonuria (PKU): An alternative therapy for maternal PKU

Abstract

Maternal phenylketonuria, PKU, has a detrimental effect on embryogenesis. Infant pathology is independent of fetal genotype, but is directly correlated with excessive phenylalaninaemia throughout pregnancy. Although normal children have been delivered by affected mothers who either had benign hyperphenylalaninaemia or in whom strict diet has apparently maintained maternal phenylalaninaemia in the low normal range from before conception, more abnormal than normal births have been reported. In addition, attempts at dietary management are often unsuccessful; most reported cases documented various severe pathological consequences of maternal PKU. Currently available methods provide viable alternative treatment. In vitro fertilization using the parental gametes, followed by implantation of the pre-embryo in a surrogate mother, would avoid a metabolic environment impairing normal development, and therefore should be recommended as alternative therapy for potential mothers with PKU.

Follow up of fetal outcome in cases of maternal phenylketonuria in Northern Ireland

“…10 11 It has even been suggested that surrogacy would provide a "safe haven" for the offspring of mothers with PKU. 12 It is now evident that the best results for mothers with PKU are obtained when phenylalanine levels are controlled before and during pregnancy. 13 14 However, ideal phenylalanine levels are not the whole answer.…”

Maternal Phenylketonuria: A New Cause for Concern

“…Although the fetus may not have the disease, elevated concentrations of phenylalanine in maternal blood can cause grave damage to the fetus (Walter, 1995). Aside from mental retardation, intrauterine growth restriction with micro-cephaly, spontaneous abortion, and congenital heart disease are other major complications associated with maternal PKU when the mother's phenylalanine concentrations exceed 20 mg/dl (Fisch, Tagatz, & Stassart, 1993).…”

“…Because of the positive amino acid gradient across the placenta, the phenylalanine concentrations in pregnancy need to be strictly controlled as in infancy and early childhood (Fisch et al, 1993). Other factors in pregnancy, such as variations in food preferences and the nausea and vomiting commonly experienced during the 1st trimester, can alter maternal blood phenylalanine concentrations and further increase the potential for nonadherence to the diet (Acosta, 1995).…”

“…Mothers who are well-educated in the disease process, the potentially hazardous effects to the fetus, and the importance of dietary control before and throughout pregnancy, are more likely to comply with nutritional therapy. Pregnancy should be discouraged if the woman lacks the motivation, commitment, intellectual capacity, or financial support to maintain the low-protein diet (Fisch et al, 1993).…”

“…Individual dietary requirements and phenylalanine tolerance vary during pregnancy among women with PKU. Phenylalanine concentrations may fluctuate daily; therefore, to maintain levels that would guarantee the birth of an unaffected infant, it would be necessary to test the mother's blood levels daily (Fisch et al, 1993). This approach, however, is neither convenient nor cost-effective.…”