Genetic ancestry analysis in non-alcoholic fatty liver disease patients from Brazil and Portugal.

Abstract

To study the association between genetic ancestry, non-alcoholic fatty liver disease (NAFLD) metabolic characteristics in two cohorts of patients, from Brazil and Portugal. We included 131 subjects from Brazil [(n = 45 with simple steatosis (S. Steatosis) and n = 86 with nonalcoholic steatohepatitis (NASH)] and 90 patients from Portugal (n = 66, S. Steatosis; n = 24, NASH). All patients had biopsy-proven NAFLD. In histologic evaluation NAFLD activity score was used to assess histology and more than 5 points defined NASH in this study. Patients were divided into two groups according to histology diagnosis: simple steatosis or non-alcoholic statohepatitis. Genetic ancestry was assessed using real-time polymerase chain reaction. Seven ancestry informative markers (AT3-I/D, LPL, Sb19.3, APO, FY-Null, PV92, and CKMM) with the greatest ethnic-geographical differential frequencies (≥ 48%) were used to define genetic ancestry. Data were analyzed using R PROJECTS software. Ancestry allele frequencies between groups were analyzed by GENEPOP online and the estimation of genetic ancestry contribution was evaluated by ADMIX-95 software. The 5% alpha-error was considered as significant (P < 0.05). In the Brazilian sample, NASH was significantly more frequent among the elderly patients with diabetes (NASH 56 ± 1.1 years old vs S. Steatosis 51 ± 1.5 years old, P = 3.7 x 10(-9)), dyslipidemia (NASH 63% vs S. Steatosis 37%, P = 0.009), higher fasting glucose levels (NASH 124 ± 5.2 vs S. Steatosis 106 ± 5.3, P = 0.001) and Homeostatic Model of Assessment index > 2.5 [NASH 5.3 (70.8%) vs S. Steatosis 4.6 (29.2%) P = 0.04]. In the Portuguese study population, dyslipidemia was present in all patients with NASH (P = 0.03) and hypertension was present in a larger percentage of subjects in the S. Steatosis group (P = 0.003, respectively). The genetic ancestry contribution among Brazilian and Portuguese individuals with NASH was similar to those with S. Steatosis from each cohort (Brazilian cohort: P = 0.75; Portuguese cohort: P = 0.97). Nonetheless, the genetic ancestry contribution of the Brazilian and Portuguese population were different, and a greater European and Amerindian ancestry contribution was detected in the Portuguese population while a higher African genetic ancestry contribution was observed in Brazilian population of both NASH and S. Steatosis groups. There was no difference between the genetic ancestry contribution among Brazilian and Portuguese individuals with NASH and S. Steatosis from each cohort.