Terry Derks has been certified as pediatrician metabolic diseases since 2013 and he is currently appointed as a metabolic pediatrician at the Beatrix children’s Hospital, University Medical Center Groningen, University of Groningen, the Netherlands. Since his PhD thesis defense in 2007 (title: “MCAD deficiency: clinical and laboratory studies”), he developed a special interest, both clinically and scientifically, in inherited disorders of glycogen metabolism (i.e. hepatic glycogen storage diseases) and mitochondrial fatty acid oxidation disorders. International sharing of knowledge and data is crucial to proceed for patients with rare diseases. As a clinical pediatric metabolic fellow, Terry has worked for 12 months at the Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil (prof dr. Moacid Wajner and prof dr. Ida Schwartz) and for 1 month at the Glycogen Storage Disease Program, Division of Pediatric Endocrinology, University of Florida, Gainesville, USA (prof dr David Weinstein). He finds especially the combining of patient care, teaching and research for patients with these rare diseases very inspiring and exciting.