Does maternal knowledge and parent education affect blood phenylalanine control in phenylketonuria?

BACKGROUND Metabolic control in phenylketonuria (PKU) may be influenced by parental ability because dietary treatment involves complex food choices. This is an observational study to compare maternal carer (MC) knowledge and parental education with phenylalanine concentrations in children with PKU. METHODS Children (n = 46; 26 boys) aged 1-10 years (median age 6 years) on dietary treatment were recruited. Their median lifetime and median phenylalanine concentrations in the year prior to study were estimated. MC completed a questionnaire to assess dietary knowledge. RESULTS Overall maternal knowledge on most aspects of diet was good and there was a correlation between annual median blood phenylalanine concentrations, but at the age of 5-6 years of age only, and higher maternal carer scores on PKU knowledge (r = -0.646; P < 0.0001). Three of only four children (12%) with median phenylalanine concentrations above 500 micromol L(-1) in the year prior to study had both parents leave school without educational qualifications. Children who had median phenylalanine concentrations (n = 3; 7%) over the recommended ranges at 3 years of age or earlier continued to have poor control. CONCLUSIONS Blood phenylalanine control within the first 3 years of age, poor parental educational achievement at school level, and unsatisfactory maternal dietary knowledge may all influence longer-term blood phenylalanine control in children.