Gilbert Syndrome and Genetic Findings in Children: A Tertiary-Center Experience from Turkey

Gilbert syndrome (GS) is a disease characterized by mildly elevated indirect serum bilirubin levels due to mutation in the promoter of the UGT1A1 gene, which causes a decrease in uridine diphosphate glucuronyltransferase enzyme activity. Gilbert syndrome should be considered based on clinical and laboratory findings in differential diagnosis, which can be supported by genetic analysis. This study aimed to evaluate the clinical findings and UGT1A1 mutations of children with Gilbert syndrome.

Patients who were admitted to the pediatric gastroenterology clinic and who were considered to have Gilbert syndrome based on clinical and laboratory findings were included in the study. The UGT1A1 analysis was performed by Sanger sequence analysis.

A total of 56 children were included in the study. A(TA)7TAA, A(TA)6TAA, and (TA)6/7 allele promoter polymorphism was detected in 75.5%, 22.5%, and 2% of the patients, respectively. Other than these, in 3 patients, 3 different sequence variants associated with GS [c.880_893delinsA (p.Tyr294MetfsTer69) and c.1091C>T(p.Pro365Leu)] were detected.

We detected 7 TA repeats in the majority of our patients. A mild bilirubin elevation was determined in cases with 6 repetitions that were not considered risky for Gilbert syndrome. We concluded that the c.880_893delinsA (p.Tyr294MetfsTer69) variant, previously shown to be associated with Crigler-Najjar syndrome type I, may also be associated with partial enzyme deficiency leading to the Gilbert syndrome phenotype.