Inclusion Criteria:
* CD study group - 'Consent form - Part 1'
1. Children with clinical suspicion for CD.
2. Between 6 and 18 years of age.
3. Naïve to any medical or nutritional intervention.
CD study group - 'Consent form - Part 2'
1. Children with CD confirmed by endoscopy (and based on accepted criteria)
2. Between 6 and 18 years of age.
3. Naïve to any medical or nutritional intervention.
Control group undergoing endoscopy children between 6 and 18 years of age undergoing colonoscopy for non-specific abdominal pain or other non-inflammatory gastrointestinal conditions.
Control group not undergoing colonoscopy
1. Children with no symptoms or signs of gastrointestinal disease and no known medical conditions.
2. Children between 6 and 18 years of age. These children will be recruited from general pediatric clinics (children attending for routine check-up), orthopedic clinics, ophthalmology clinics or schools.
Exclusion Criteria:
* CD study group
1. Any known autoimmune or rheumatologic disease.
2. Chronic gastro-intestinal disorder (e.g. celiac disease, eosinophilic esophagitis, collagenous gastritis, autoimmune gastritis, etc.).
3. Past or present history of malignancy.
4. Primary immunodeficiency.
5. Pregnancy in the last 6 months, breastfeeding.
6. Morbid obesity (BMI \> 95th percentile for their age and gender).
7. Following particular dietary regimen/dietitian consultation/participation in another study.
8. Chronic treatment with any oral/systemic immunosuppressive or anti-inflammatory drugs (e.g. steroids, 5-aminosalicylic acid, immunomodulators, biologics, etc.). Patients receiving these drugs as inhalors/creams/ointments should not be excluded from the study.
9. Use of systemic antibiotics, probiotics or NSAIDs during 30 days prior to enrollment.
10. Gut-related surgery, including bariatric surgery.
11. Inability of the participant and nuclear family to follow and utilize the smartphone application.
Control group undergoing endoscopy:
1. Any known autoimmune or rheumatologic disease.
2. Chronic gastro-intestinal disorder (e.g. celiac disease, eosinophilic esophagitis, collagenous gastritis, autoimmune gastritis, etc.).
3. Past or present history of malignancy.
4. Primary immunodeficiency.
5. Pregnancy in the last 6 months, breastfeeding.
6. Morbid obesity (BMI \> 95th percentile for their age and gender).
7. Following particular dietary regimen/dietitian consultation/participation in another study.
8. Chronic treatment with any oral/systemic immunosuppressive or anti-inflammatory drugs (e.g. steroids, 5-aminosalicylic acid, immunomodulators, biologics, etc.). Patients receiving these drugs as inhalors/creams/ointments should not be excluded from the study.
9. Use of systemic antibiotics, probiotics or NSAIDs during 30 days prior to enrollment.
10. Gut-related surgery, including bariatric surgery.
Control group not undergoing colonoscopy:
1. Any known autoimmune or rheumatologic disease.
2. Chronic gastro-intestinal disorder (e.g. celiac disease, eosinophilic esophagitis, collagenous gastritis, autoimmune gastritis, etc.).
3. Past or present history of malignancy.
4. Primary immunodeficiency.
5. Pregnancy in the last 6 months, breastfeeding.
6. Morbid obesity (BMI \> 95th percentile for their age and gender).
7. Following particular dietary regimen/dietitian consultation/participation in another study.
8. Chronic treatment with any oral/systemic immunosuppressive or anti-inflammatory drugs (e.g. steroids, 5-aminosalicylic acid, immunomodulators, biologics, etc.). Patients receiving these drugs as inhalors/creams/ointments should not be excluded from the study.
9. Use of systemic antibiotics, probiotics or NSAIDs during 30 days prior to enrollment.
10. Gut-related surgery, including bariatric surgery.
