Combo group included children on combination anti-TNF-α and immunosuppressant therapy; children undergoing anti-TNF-α monotherapy were assigned to Mono group.<h4>Results</h4>One hundred and seventeen children were enrolled, of whom 74 (63.2%) were affected by Crohn's disease (CD) and 43 (36.8%) by ulcerative Colitis (UC) (median age at diagnosis: 11.6 years; range 2.1-16.9; M/F: 56/61). The gene discussed is TNF; the disease is Crohn disease.