In the majority of enrolled subjects, clinical jaundice was accidently observed during puberty or early adult life in agreement with previous studies [1, 7, 28] given that some subjects with GS are born with varying amounts of UGT1A1 enzyme activity that may support bilirubin conjugation during early childhood but is not sufficient for complete conjugation during adult life and increased activities [11]. This evidence concerns the gene UGT1A1 and Jaundice.