RESUMO
Background: In Europeans the TATA box TA7 repeat promoter variant in the UGT1A1 gene (UGT1A1*28) is the major determinant of bilirubin levels. Aim: To study the prevalence of Gilbert Syndrome (GS) and its genetic determinants in Chile. Material and Methods: Three different studies were conducted. The prevalence of GS in Chile was assessed in 991 subjects with normal liver tests (ALT and GGT) from the 2nd National Health Survey. We defined GS as a total bilirubin (TB) between 1.4-5mg/dL. The second study assessed the genotype prevalence of SNP rs6742078 (in LD with UGT1A1*28) and rs4149056 in 500 DNA samples of non-related Hispanics. Finally, a case-control study was designed to assess the phenotype-genotype correlation. UGT1A1*28 and rs4149056 variants were determined by direct sequencing and allelic discrimination assays (TaqMan), respectively. Results: Prevalence of GS in the general Chilean population was 2.6% (4.5% in males and 0.5% in female). No correlation with age, educational level or home location was found. Genotypes for UGT1A1*28 (TA6/6 50.5%, TA6/7 37.8%, TA7/7 11.7%) and rs4149056 (TT 74.1%, CT 22.8%, and CC 3.1%) variants were similar to Europeans. In the case-control study, most patients with GS were homozygotes for UGT1A1*28 (TA7/7, 74%). Of note, 44% of patients with intermediate TB levels were also TA7/7, compared to 7% in normal subjects. SLCO1B1 genotype was not correlated with TB levels. Conclusions: While the prevalence of GS was lower in Chile compared to Europeans (~5%), the prevalence of UGT1A1*28 homozygotes was similar (~12%). In Chilean Hispanics, the UGT1A1*28 variant explain 75% of GS phenotype.
Assuntos
Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Bilirrubina/genética , Estudos de Associação Genética , Doença de Gilbert/epidemiologia , Glucuronosiltransferase , Coleta de Amostras Sanguíneas , Estudos de Casos e Controles , Chile/epidemiologia , População Branca/genética , Interação Gene-Ambiente , Doença de Gilbert/genética , PrevalênciaRESUMO
Crigler-Najjar syndrome is a rare autosomal recessive disease caused by mutations in the UGT1A1 gene. These mutations result in the deficiency of UGT1A1, a hepatic enzyme essential for bilirubin conjugation. This report describes the case of a 4-month-old boy with the cardinal symptoms of Crigler-Najjar syndrome type II. Molecular genetic analysis showed a homozygous UGT1A1 promoter mutation [A(TA)7TAA] and a heterozygous insertion of 1 adenosine nucleotide between positions 353 and 354 in exon 1 of UGT1A1 that caused a frameshift with a premature stop codon.
Assuntos
Bilirrubina/genética , Síndrome de Crigler-Najjar/genética , Glucuronosiltransferase/genética , Regiões Promotoras Genéticas , Povo Asiático/genética , Bilirrubina/metabolismo , Códon sem Sentido/genética , Síndrome de Crigler-Najjar/patologia , Éxons , Mutação da Fase de Leitura , Heterozigoto , Homozigoto , Humanos , Recém-Nascido , Masculino , Polimorfismo de Nucleotídeo ÚnicoRESUMO
BACKGROUND: In Europeans the TATA box TA7 repeat promoter variant in the UGT1A1 gene (UGT1A1*28) is the major determinant of bilirubin levels. AIM: To study the prevalence of Gilbert Syndrome (GS) and its genetic determinants in Chile. MATERIAL AND METHODS: Three different studies were conducted. The prevalence of GS in Chile was assessed in 991 subjects with normal liver tests (ALT and GGT) from the 2nd National Health Survey. We defined GS as a total bilirubin (TB) between 1.4-5mg/dL. The second study assessed the genotype prevalence of SNP rs6742078 (in LD with UGT1A1*28) and rs4149056 in 500 DNA samples of non-related Hispanics. Finally, a case-control study was designed to assess the phenotype-genotype correlation. UGT1A1*28 and rs4149056 variants were determined by direct sequencing and allelic discrimination assays (TaqMan), respectively. RESULTS: Prevalence of GS in the general Chilean population was 2.6% (4.5% in males and 0.5% in female). No correlation with age, educational level or home location was found. Genotypes for UGT1A1*28 (TA6/6 50.5%, TA6/7 37.8%, TA7/7 11.7%) and rs4149056 (TT 74.1%, CT 22.8%, and CC 3.1%) variants were similar to Europeans. In the case-control study, most patients with GS were homozygotes for UGT1A1*28 (TA7/7, 74%). Of note, 44% of patients with intermediate TB levels were also TA7/7, compared to 7% in normal subjects. SLCO1B1 genotype was not correlated with TB levels. CONCLUSIONS: While the prevalence of GS was lower in Chile compared to Europeans (~5%), the prevalence of UGT1A1*28 homozygotes was similar (~12%). In Chilean Hispanics, the UGT1A1*28 variant explain 75% of GS phenotype.
Assuntos
Bilirrubina/genética , Estudos de Associação Genética , Doença de Gilbert/epidemiologia , Glucuronosiltransferase , Adulto , Idoso , Idoso de 80 Anos ou mais , Coleta de Amostras Sanguíneas , Estudos de Casos e Controles , Chile/epidemiologia , Feminino , Interação Gene-Ambiente , Doença de Gilbert/genética , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , População Branca/genéticaRESUMO
Highly active antiretroviral therapy (HAART) has increased the survival of HIV-infected patients. However, adverse effects play a major role in adherence to HAART. Some protease inhibitors (mainly atazanavir and indinavir) act as inhibitors of uridine diphosphate-glucuronosyltransferase (UGT1A1), the enzyme responsible for hepatic conjugation of bilirubin. Variations in the promoter region of the UGT1A1 gene (UGT1A1*28, rs8175347) can influence bilirubin plasma levels, modulating the susceptibility to hyperbilirubinemia. Aiming to analyze the association between UGT1A1*28 allele and hyperbilirubinemia in individuals exposed to HAART, we evaluated 375 HIV-positive individuals on antiretroviral therapy. Individuals carrying the UGT1A1*28 allele had a higher risk of developing severe hyperbilirubinemia [prevalence ratio (PR)=2.43, 95% confidence interval (CI) 1.08-5.45, p=0.032] as well as atazanavir users (PR=7.72, 95% CI=3.14-18.98, p<0.001). This is the first description of such an association in Brazilian HIV patients, which shows that in African-American and Euroamerican HAART users, the UGT1A1*28 allele also predisposes to severe hyperbilirubinemia, especially in those exposed to atazanavir.