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.

Inclusion Criteria:

• To be included in the short stature group, subjects must have had short stature, defined height less than -2 SD for gender and age or an abnormal growth velocity for gender and age).
• To be included in the failure-to-thrive group, subjects must have had poor weight gain, defined as weight less than -2 SD for gender and age or an abnormal weight velocity for gender and age.
• Patients in both groups will be evaluated for the presence of chronic gastrointestinal symptoms, defined as symptoms of gastrointestinal disease for greater than 6 weeks or recurrent symptoms. Patients who were affected in both weight and height will be stratified by which measurement was more severely affected, with poor weight gain being the primary problem in the "failure-to-thrive" grouping (Group 2) and "poor linear growth" being the primary problem in the short stature group (Group 1).
• Patients who have had chronic gastrointestinal symptoms, defined as symptoms of gastrointestinal disease for greater than 6 weeks or recurrent symptoms, but normal stature and growth, will be analyzed separately (Group 3).

Exclusion Criteria:

• Must not have a known diagnosis as an etiology for growth failure or GI symptoms prior to presentation.

Twenty-five (25) patients seen for evaluation of short stature in the pediatric endocrinology clinic will have serum ghrelin levels measured in addition to their usual routine bloods tests.

Twenty-five (25) patients will be selected from patients who present with chronic gastrointestinal symptoms (symptoms of gastrointestinal disease for greater than 6 weeks or recurrent symptoms) and who have poor growth.

The remaining 25 will be selected from patients with chronic gastrointestinal symptoms (symptoms of gastrointestinal disease for greater than 6 weeks or recurrent symptoms) who have normal growth.