Multicenter study on long-term growth in patients with phenylketonuria.

INTRODUCTION

Most of the studies on PKU have focused on the neurological development of patients. Studies regarding the physical development usually cover a short period of time, do not include dietary information, and results are contradictory. The aim of this study is to determine whether the patients with PKU have a normal growth, the incidence of obesity and the relationship of these parameters with diet and nutritional intake.

MATERIAL AND METHODS

This is a retrospective, multicenter, multinational study including patients with PKU from 8 centers from different countries. Data of growth parameters and dietary regimes were collected from birth until the age of 18 years. Anthropometric tools of the WHO (Anthro version 3.2.2 and Anthro plus) were used to calculate z-score for weight-for-age, height-for-age and body mass index (BMI).

RESULTS

Data from 182 patients with classical PKU were included. The median height z-scores for both male and female patients showed a normal growth pattern according to the WHO charts. Significant positive correlation  was observed between height z-score and the Phe (mg/day) and natural protein (g/day) intakes in all ages, especially in children younger than 11 years. The amount of Phe-free amino acid mixture did not affect the height, but lower intakes were negative correlated with the BMI. Also, we detected a positive correlation between the median Phe levels and BMI, meaning that the poorer metabolic control was correlated with higher BMI.

CONCLUSIONS

An objective of PKU is that patients have satisfactory final physical development; the height prognosis seems to be associated with Phe and natural protein intake and therefore should be optimized. It is important to collect longitudinal growth data throughout childhood and adolescence in PKU that considers any change in growth in relationship to dietary patterns.