In 13 patients, blood chemistry tests were performed after the onset of symptoms; in particular, we evaluated indices of liver function (aspartate aminotransferase-AST, alanine aminotransferase-ALT, total bilirubin), cholestasis (Gamma-glutamyl Transferase-GGT, Alkaline Phosphatase-ALP, direct bilirubin) and leukocytosis as the main inflammatory index. The gene discussed is GPT; the disease is cholestasis.