[Polymorphisms of the UDP-glucuronosyltransferase 1-A1 gene in Tunisian population]

The UDP-glucuronosyltransferase 1A1 gene that encode the enzyme UGT1A1 responsible for glucuronidation undergoes several variations that may affect the enzymatic activity or expression and which are the cause of metabolic disorders related to the glucuronidation of bilirubin, such as Gilbert's syndrome and Crigler Najjar's syndrome. Among the most common variations, there is the repeat polymorphism A (TA) n TAA in TATA box and biallelic mutation G211A in exon 1. We consider in this work to determine their frequencies in a healthy population. The polymorphism A (TA) n TAA showed that genotype [TA7/TA7] was described as being associated with Gilbert's syndrome and was encountered in 11% of the population studied. This percentage is close to the value described in the Caucasian population, estimated at 10%. Concerning the polymorphism G211A, our results show that the mutated allele is encountered in 15.7% of our study population. This frequency differs greatly from that reported for Caucasians and Afro-Americans but it is similar to that perceived at the Japanese. All these results suggest that the Tunisian population appears to be heterogeneous view UGT1A1 gene mutation status. Regarding the origins and distribution of such polymorphisms in our population, the study reveals a high haplotypic haplotype (TA) 6-G considered ancestral. The comparison of the haplotype structure generally leads to the development of a hypothetical tree of the origin and spread of different haplotypes.