The Major Changes of Gilbert’s Syndrome and UGT1A1 Gene Abnormalities in Mongolians Are Western Type = The Major Changes of Gilbert’s Syndrome and UGT1A1 Gene Abnormalities in Mongolians Are Western Type

다국어 초록 (Multilingual Abstract)

Aims: Hereditary abnormalities of uridinediphosphoglucuronate-glucuronosyltransferase 1A1 (UGT1A1) gene is the major cause of unconjugated hyper-bilirubinemia. The abnormalities of UGT1A1 gene in Mongolian population remain uninvestigated. Eight in 99 consecutive Mongolian adults developed indirect hyperbilirubinemia. We therefore studied Mongolian patients for GS and UGT1A1 abnormalities. Methods: Between 2007 and 2014, ninety-nine consecutive Mongolian adult patients of chronic liver disease from the Department of Gastroenterology, Mongolian National University of Medical Sciences were studied. Eight (8.1%) of them developed indirect hyperbilirubinemia. All patients were tests for blood chemistries, hemoglobin, international normalized ratio (INR), mean corpuscular volume (MCV), glucose-6-phosphate dehydrogenase (G6PD) levels as well as UGT1A1 genetic abnormalities. We genotyped the UGT1A1 gene for the A(TA)6TAA (6) or A(TA)7TAA (7) promoter variant, and the coding region for nucleotide mutations (nt)-211 G to A, nt-686 C to A, nt-1091 C to T and nt-1456 T to G. Results: Among the eight patients that developed indirect hyperbilirubinemia, six were male and two were female. All patients had hemoglobin, INR, MCV and G6PD levels within normal limit and we excluded possibility of anemia, decompensated liver function, thalassemia and G6PD deficiency. Our data confirms two variants of the UGT1A1 gene among the Mongolian patients. Two case were homozygous for nt-211G>A mutation, two case heterozygous for 6/7 promoter variants and nt-211G>A mutation, whereas four case were typical GS with homozygous 7/7 promoter genotype with no mutation in the coding region None of our Mongolian patients had mutations at nt-686, nt-1091 or nt-1456. Conclusions: Our pilot results show that GS and UGT1A1 abnormalities are common in Mongolians. Prevalence of the UGT1A1 promoter abnormalities in Mongolians are similar to the Western population; whereas the high prevalence of nt-211G>A variant is similar to the Asians. Further studies with much larger number of patients are necessary to confirm the genetic status of GS and UGT1A1 variants in Mongolians.