Growth and skeletal maturation in children with phenylketonuria

Abstract

Growth and skeletal maturation was evaluated in 82 children participating in the German Collaborative Study of Children Treated for Phenylketonuria (PKU). Height, weight, head circumference and bone age were recorded at regular intervals for the first 6 years of life. The mean SD score (SDS) for height was not significantly different from zero at study entry, but decreased mainly during the second year of life to a nadir of -0.78 in boys and -0.54 in girls at 2.5 years. During the subsequent years, a significant trend towards a regain of height SDS was noted in both sexes. Weight-for-height SDS was close to zero in both sexes, with a significant continuous increasing trend throughout the observation period. Head circumference SDS decreased in boys during the first year of life from -0.28 to -0.68, whereas girls showed only a minor change. During the further follow-up period, head circumference SDS remained at approximately -0.3 in boys and 0.0 in girls. While the mean verbal and performance IQ of the total study population at 5 and 6 years of age did not differ from a group of 212 healthy non-PKU children, patients with a head circumference SDS less than the population median at 2 years of age exhibited poorer cognitive abilities at school age than those patients with a relative head size greater than the population median. The children with a head circumference less than the median at 2 years had smaller head sizes already at birth; in addition, the change in relative head size during the first 2 years was correlated significantly with cognitive abilities at school age in boys. Mean bone age was identical to chronological age at each time point of observation. The rate of maturation was one year of bone age per year of chronological age. No correlation between phenylalanine intake or phenylalanine concentrations and the rates of body or head growth or skeletal maturation could be established. We conclude that despite adequate weight gain, moderate growth retardation occurred during the first 2 years of life in this group of children treated for PKU. Growth was more compromised in boys than in girls and tended to be compensated during later follow-up. Early infantile head circumference and growth appear to be predictors of cognitive development.

Evaluation of Physical Growth and Weight Patterns of Egyptian Children with Phenylketonuria under a Phenylalanine-Restricted Diet

“…Further, those children below the 3rd percentile for weight at baseline reached normal growth after 2 years, but most of those below the 3rd percentile for height did not reach normal growth after 2 years. Previously published European studies found growth retardation of PKU patients during the first years of life was followed by restoration of normal growth [9,[22][23][24] A longitudinal study of Dutch children found that those with PKU had an almost identical height as other children of the same age [9]. Although normal growth appeared to be restored for weight in the current study, the normal growth for height for the PKU children was not restored.…”

Intellectual development of the patients of the German Collaborative Study of children treated for phenylketonuria

“…This recommendation, at that time very strict, can nowadays be found in general recommendations for treating PKU [15,25]. Details of the design and protocol as well of results have been reported elsewhere [3,5,19,[21][22][23]28] and in the present issue of the European Journal of Pediatrics. The data presented in this paper concentrate on the development of intelligence of the patients from 4 "to 9 years of life in relation to their blood Phe levels during the first 9 years of life.…”

Recommendations for protein and energy intakes by patients with phenylketonuria

“…The report by Dhondt et al [5] of growth of 94 French patients indicated that both at birth and at 8 years of age, mean Z-scores for height and weight were negative. Schaefer et al [21] reported that mean standard deviation scores (SDS) for height and weight at birth of 82 German Collaborative Study patients did not differ from 0. During the first 2 years of life, the mean SDS became negative but returned toward 0 during the following 3 years.…”

“…Weglage et al [23] found negative mean Zscores for height during the first 18 months of life in 87 German patients. Only Schaefer et al [21] and Weglage et al [23] reported protein intakes and none reported energy intakes. Schaefer et al [21] reported that protein intake was 2.24 + 0.51 g/kg (mean + SD) during the first 2 years of life and 1.98 + 0.25 g/kg until 6 years of age.…”

“…Only Schaefer et al [21] and Weglage et al [23] reported protein intakes and none reported energy intakes. Schaefer et al [21] reported that protein intake was 2.24 + 0.51 g/kg (mean + SD) during the first 2 years of life and 1.98 + 0.25 g/kg until 6 years of age. Weglage et al [23] reported that protein intake during the 1st year of life was 2.5 g/kg per day and was 2 g/kg per day between 2 and 5 years.…”