Ghrelin Levels in Children With Poor Growth

The investigators hypothesize that low serum ghrelin levels may characterize a group of patients with poor weight gain and/or linear growth who do not have any other identified cause for growth failure. These patients may present with a variety of complaints and are often evaluated by both pediatric endocrinologists and pediatric gastroenterologists. The investigators hypothesize that ghrelin has a physiologically important role in linear growth and that chronic diseases of the gastrointestinal system, such as H. Pylori infection or celiac disease, may alter serum ghrelin levels in children. Low ghrelin levels may be a factor leading to poor growth, potentially by altering growth hormone secretion and/or by decreasing appetite. By measuring ghrelin levels in children with short stature and in children with gastrointestinal disease, the investigators will further elucidate the possible physiologic role of ghrelin in childhood growth and how it may be altered in conditions causing short stature and in certain gastrointestinal diseases.