Late effects of phenylketonuria

Hypomelanotic Conditions of the Newborn and Infant

Depigmented nevi, pityriasis alba, and postinflammatory hypopigmentation are the most frequent hypomelanotic conditions in newborns and infants. These, and examples of less frequent hypopigmentations are briefly discussed in this article. A new classification for depigmented nevi is also proposed.

Adult phenylketonuria

Newborn screening for phenylketonuria began 35 to 40 years ago in most industrialized countries. Because of this initiative, which resulted in early institution of phenylalanine-restricted diets, there are now many young adults with this disease who have normal or near-normal intellectual function. In North America alone, 200 patients with phenylketonuria enter adulthood every year. Most expert panels recommend following a phenylalanine-restricted "diet for life." However, there are few adult physicians dedicated to continuing care of this group, with the possible exception of maternal phenylketonuria. Up to 10% of adults with classic phenylketonuria, and possibly 50% of those with milder variants, may not need treatment; after adolescence, intelligence does not appear to deteriorate, at least into early adulthood, even if diet therapy is discontinued or not in good control. However, neuropsychological and psychosocial problems develop frequently, needing focused and intensive support by health care providers. New investigative methods and treatment options are on the horizon. There is an urgent need for physicians who will orchestrate the care of adults with phenylketonuria.

Blood phenylalanine control in adolescents with phenylketonuria

In order to determine the degree of compliance with dietary treatment in adolescents with phenylketonuria (PKU) we have analysed blood phenylalanine (phe) results in 75 patients (42 male) aged between 10 and 20 years. We compared these results with the upper limit for blood phe and the blood sampling frequency as recommended by the United Kingdom's National Society for Phenylketonuria (NSPKU(UK)). The blood phe increased with age from a mean (1SD) of 0.51 mmol/l (0.19) at 10 years to 0.98 mmol/l (0.30) by 20 years. A mean of 17% (24) of samples were above the recommended range at 10 years, but this had increased to a mean of 75% (33) by 20 yrs. The frequency of blood sampling fell from a mean of 83% (32) of that recommended to under 51% (37) by 20 years. Control was not significantly better in females compared with males. We conclude that although compliance with treatment in PKU is acceptable for most patients at 10 years this is not the case by late adolescents and early adulthood.

Assessment of adult phenylketonuria

Phenylketonuria (PKU) has been detected on the newborn screening programme since the 1960s. Although it is recognised that dietary treatment is successful in avoiding the severe mental retardation associated with untreated PKU, the long-term outcome for adults remains unclear. The Medical Research Council recommends that the diet be followed for life. This paper discusses the relevance of the findings of neurological deterioration, neuropsychological problems and brain imaging in adults with PKU. It suggests an approach to follow-up for adults with PKU including neurological assessments, awareness of nutritional deficiencies, educational requirements and the risks of maternal PKU.

Maternal phenylketonuria: a new cause for concern

The start of newborn screening for phenylketonuria (PKU) during the early 1970s has given rise to an increasing number of women who have been identified and successfully treated for the disease in childhood and are now preparing to have children of their own. Early detection and initiation of nutritional therapy before conception is key to a successful pregnancy outcome. Nurses who understand the pathophysiology, dietary limitations, and management of PKU in pregnancy can provide the care necessary for optimal maternal and neonatal health.