Impaired Insulin-like Growth Factor-1 (IGF-1) Generation Causes Protein Catabolism and Poor Growth in Children With Crohn Disease

The investigators will prospectively recruit 26 children with moderate - severe active Crohn disease (PCDAI \>30). Results will be compared to 26 patients in sustained remission (PCDAI \<10 and physician global assessment of remission over the previous 6 months) who are matched for age and gender. Subjects will be studied at baseline and six months. The primary study end-points will be leucine rate of appearance (a measure of protein breakdown) and IGF-1 levels. This study will test the hypothesis that children with greater disease severity will have worse longitudinal growth and protein catabolism. The investigators will also explore the secondary hypothesis that children with Crohn disease have abnormal IGF-1 generation which is linked to underlying inflammation and disease severity.