UGT1A1 (TA)n genotype is not the major risk factor of cholelithiasis in sickle cell disease children.

OBJECTIVES: Because of the increased hemolytic rate, a significant proportion of patients with sickle cell disease (SCD) are prone to develop cholelithiasis. The present study investigated the role of several genetic factors (UGT1A1 promoter (TA)n repeat polymorphism, alpha-globin status), hematological parameters, clinical severity, and hydroxyurea (HU) therapy on the occurrence of cholelithiasis in SCD.

METHODS: One hundred and fifty-eight children (2-18 yr old) regularly followed at the University Hospital of Lyon (France) were included. A multivariate Cox model was used to test the associations between cholelithiasis and the different parameters analyzed.

RESULTS: We confirmed that alpha-thalassemia and low basal reticulocyte (RET) count were independent protective factors for cholelithiasis while 7/7, 8/8 and 7/8 UGT1A1 (TA)n genotypes were independent predisposing factors for this complication. We also showed for the first time that HU treatment decreased the risk for cholelithiasis while frequent vaso-occlusive crises and acute chest syndrome events increased that risk.

CONCLUSIONS: Our findings demonstrate that UGT1A1 (TA)n polymorphism is not the only factor triggering gallstone formation in SCD. Cholelithiasis is also modulated by RET count, the number of deleted alpha-genes, HU therapy and the frequency of vaso-occlusive events.