11 Background Recently a new DNA virus has been reported in patients with posttransfusion hepatitis of unknown etiology, in blood donors and in patients with cryptogenic cirrhosis and fulminant hepatic failure. Neverthless the several reports, it is not yet clear the role of TTV in the pathogenisis of acute and chronic liver disease. Furthermore, there are no data on the role of TTV in paediatric patients with cryptogenic hepatitis. Patients and Methods Stored sera of eight children (age, range: 4-10 years) who referred to our Department for cryptogenic hepatitis were retrospectively studied. All patients had no serological markers for A-G hepatitis, HIV, TORCH, EBV. Metabolic and genetic causes of liver disease were also excluded. TTV DNA was extracted from serum samples using DNAzol reagent. Semi-nested PCR was used to amplify 279 bp of TTV DNA, as previously described by Naoumov NV et al. Results TTV-DNA has been found in all sera tested from one out eight children studied. The patient presented in 1996 at the age of four years old for cryptogenic hepatitis and associated extrahepatic symptoms, namely arthritis, myositis, skin rush, recurrent fever and weight loss. Liver biopsy showed the histological picture of mild chronic hepatitis and mild bile duct proliferation. Any therapeutic attempt with steroidal and non-steroidal anti-inflammatory agents was without benefit on the hepatic and systemic symptoms. The enteral nutrition with elemental formulas, established for the appearance of abdominal pain and gastrointestinal signs of inflammatory bowel disease, resulted effective in restoring nutritional status but did not significantly affect the hepatic function. Conclusions The TTV-DNA was detected in a child with a clinical history of idiopathic chronic hepatitis and associated autoimmune extrahepatic symptoms. Further follow-up and evaluation will be necessary to clarify the exact role of TTV in the pathogenesis of hepatic and extrahepatic manifestations in this patients, especially for a more appropriate therapeutic approach. Larger investigations of TTV in paediatric patients with posttransfusional and cryptogenic hepatitis are required.