Clinical burden of illness in patients with phenylketonuria (PKU) and associated comorbidities - a retrospective study of German health insurance claims data oleh K. F. Trefz, A. C. Muntau, K. M. Kohlscheen, J. Altevers, C. Jacob, S. Braun, W. Greiner, A. Jha, M. Jain, I. Alvarez, P. Lane, C. Schröder, F. Rutsch