Infection in Children with Phenylketonuria Does Not Depend on Metabolic Control and Is Not More Frequent Than in Healthy Subjects-A Cross-Sectional Study

In a small preliminary study, phenylketonuria and poor metabolic control were suggested as risk factors for infection in children as detected with an antigen stool test. We aimed to determine prevalence in an adequately sized group of individuals with phenylketonuria and healthy subjects using the standard gold test (urea breath test). Further, we correlated infection with metabolic control. The study comprised 103 individuals with phenylketonuria and 103 healthy subjects on whom a C urea breath test was performed. Blood phenylalanine levels in the preceding year were analysed. The infection rate did not differ between individuals with phenylketonuria and healthy subjects (10.7% vs 15.5%; = 0.41). The frequency of testing and phenylalanine concentrations of -positive and -negative patients with phenylketonuria did not differ ( = 0.92 and = 0.54, respectively). No associations were detected for body mass index or metabolic control. Forward stepwise regression models revealed that age ( 0.0009-0.0016) was the only independent correlate of infection with a relatively low fraction of the variability of the condition being explained (adjR = 0.0721-0.0754; model = 0.020-0.023). In conclusion, infection in phenylketonuria is not more frequent than in the general population. Moreover, it does not depend on metabolic control.