MOLECULAR-GENETIC TESTING FOR GILBERT’S SYNDROME
Abstract
The article discusses the features of the UGT1A1 gene polymorphism, which represents an urgent problem in diagnosing Gilbert’s syndrome using the gene polymorphism genotyping method and is of clinical interest in detecting the manifestation of hyperbilirubinemia in newborns, as well as in selecting patients who need clinical observation. The purpose of the work was to study the UGT1A1 genotype in patients with Gilbert’s syndrome and its effect on the clinical manifestations of the disease. The material for the study was DNA samples obtained from 253 patients observed by a gastroenterologist and examined between 2013 and 2024. Among the patients there were 85 women and 168 men aged from 15 to 46 years. DNA was isolated from peripheral blood using the DNA-express reagent (NPO Litech, Russia). The polymerase chain reaction of the DNA fragment under study was carried out on a programmable thermal cycler Tertsik-MS2 (DNA-technology, Russia) using SNP UGT1A1 kits (NPO Litech, Russia). The level of bilirubin, alanine aminotransferase and aspartate aminotransferase in the blood serum of patients was determined using LaChema kits (Czech Republic), measuring optical density on a Specord spectrophotometer (Germany). It was established that the presence of a genetic defect such as a dinucleotide insertion in the promoter region of the UDP-GT1 gene is a risk factor for the development of hyperbilirubinemia due to a decrease in the activity of the UDP-GT1 enzyme. Clinical manifestations of Gilbert’s syndrome are observed not only in patients with a mutant homozygous UGT1A1 7/7, but also in cases with a heterozygous variant of the UGT1A1 6/7 gene. Genetic testing of the UGT1A1 polymorphism is a necessary component of the diagnosis of Gilbert’s syndrome and the treatment of patients to limit excessive exercise, stress, fasting, dehydration and hypothermia.
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