Fractures and phenylketonuria.

Parent or self-reported history of fractures in a group of patients aged from 0.3 to 33.6 years on dietary treatment for phenylketonuria was studied by means of a questionnaire. Twenty-one of 85 patients had a history of fracture compared with 18/98 sibling controls. There was no significant difference in the lifetime risk of fracture between patients and controls (chi 2 = 1.43, df = 1, p = 0.23), but a significantly higher risk of fracture was reported over the age of 8 y (chi 2 = 5.11, df = 1, p = 0.024), with a relative risk of 2.6 (95% confidence interval 1.1.6.1). We suggest this may be related either to deterioration in dietary control in this age group or to a cumulative disease-related or diet-related reduction in bone mass.