Maternal phenylketonuria: a continuing problem

Objectives: To estimate the number of women of childbearing age in New Sout h Wales whose children are at risk of the maternal phenylketonuria (PKU) sy ndrome (intellectual disability, microcephaly, congenital malformations). Setting: New South Wales, 1996. Design: Comparison of number of women with PKU aged 15-44 years on the NSW PKU database (observed number) with expected number derived from population data. Main outcome measures: Observed and expected numbers of women with PKU (def ined as blood phenylalanine levels greater than or equal to 400 mu mol/L, a nd phenylalanine-restricted diet recommended) by age; number with no clinic al contact with the PKU service in previous year; outcomes of pregnancies i n women with PKU (January 1994 to July 1996). Results: 110 women aged 15-44 years with PKU were listed on the database. T he expected number was 145 (95% confidence interval, 122-171). The differen ce was greatest in the 30-44 years age group (born before comprehensive new born screening), with only 55% of the expected number listed. Sixteen women who had been diagnosed with PKU at birth were not having regular follow-up , while 18 women had been diagnosed only after investigation of abnormaliti es in their children. Of 28 pregnancies managed by the NSW PKU service, 19 were considered unaffected by the maternal PKU syndrome and five affected ( another three did not reach term; one outcome was unknown). Of 46 unmanaged pregnancies, all were affected. Conclusion: There is an urgent need for better follow-up of women with PKU and for education of health professionals about the MPKU syndrome, its reco gnition, the risks of untreated pregnancy and the benefits of dietary treat ment.