Gilbert Syndrome, is a benign condition characterized by persistent indirect hyperbilirubinemia due to reduced UDP-glucuronyltransferase enzyme activity. Its coexistence with other clinical disorders has important clinical and pharmacological implications. GS is known to coexist with many hemolytic conditions and may lead to diagnostic difficulty and also increased incidence of gallstones. UGT1A1 gene has been shown to be involved in the conjugation of various physiologically important endogenous and exogenous compounds, so individuals with Gilbert mutation (the variant allele UGT1A1*28) have an increased risk of toxicity of various drugs and endogenous compounds like irinotecan, steroid hormones, implicated in various human carcinoma like colorectal and breast carcinoma. Deferiprone (DFP) is an orally available chelator used in the management of iron overload in patients with Transfusion Dependent Thalassemia (TDT). In this study, fifteen out of 275 patients with TDT, had a deferiprone-induced joint deformity. Among these fifteen patients with joint deformity, eleven patients (four patients were homozygous for TA 7 repeats and seven were heterozygous for TA7 repeats) had associated gilbert mutation. Therefore, we hypothesize that patients of TDT who had underlying Gilbert mutation might have decreased enzymatic activity of UGTIA6, which metabolizes the DFP, leading to more prominent adverse effects related to DFP.