Crohn disease is a disorder characterized by inflammation of any portion of the gastrointestinal tract, from mouth to anus. Extraintestinal manifestations of the disease include arthralgias, ankylosing spondylitis, myalgias/myositis, uveitis, vasculitis, and sclerosing cholangitis. Skin manifestations include erythema nodosum and pyoderma gangrenosum. Granulomatous dermatitis or metastatic Crohn disease is rare in childhood. Although extensive published data exist on genetic, infectious, immunologic, and psychologic aspects of Crohn disease, the role of mitochondrial dysfunction as a primary or contributory cause has not been studied.

We report a pediatric patient with muscle weakness, seizures, and respiratory insufficiency beginning at age 1 year, who experienced severe metastatic Crohn disease at 8 years of age. She experienced no response to antibiotics, steroids, or bowel rest but showed dramatic improvement with anti–tumor necrosis factor-alpha (TNF-α) antibody (infliximab). The response to infliximab suggested that she might have some mitochondrial dysfunction (1, 2). Her normal mononuclear cell thymidine phosphorylase activity ruled out the possibility of mitochondrial neurogastrointestinal encephalomyelopathy syndrome (MNGIE). Studies of mitochondrial oxidative phosphorylation revealed functional defects at Complex III and IV in isolated muscle mitochondria which suggest that mitochondrial dysfunction might play a role in the pathogenesis of her condition.