The Influence of Autophagy on Nonalcoholic Fatty Liver Disease

The investigators will perform a prospective comparison of the genotype distribution of autophagy pathway-related genetic polymorphisms between those with and without NAFLD in a cohort of obese children and adolescents.

[Subjects] Obesity is defined as the BMI value > 95 percentile by different age- and gender groups according to the standards of the Department of Health in Taiwan.

[Data collection] The following data were obtained for each subject: age, gender, BMI, waist and hip circumference. The investigators will measure total serum bilirubin, alanine aminotransferase, aspartate aminotransferase, γ-glutamyltransferase fasting glucose, triglyceride, total cholesterol, and high-density lipoprotein cholesterol, insulin, glucose, and adiponectin.

[Liver ultrasonography] All participants will receive an ultrasonographic study of the liver. NAFLD is defined as the presence of an ultrasonographic pattern consistent with the following criteria: liver-kidney echo discrepancy, attenuated echo penetration and visibility of diaphragm, and obscure hepatic vessel structures.

[Genotyping] Genomic DNA will be extracted from 3 cc venous blood from each participant. After extraction, the genomic DNA will be immediately stored at -80°C. The TaqMan genotyping assays will be performed for selected SNPs genotyping on ABI 7300 Real-Time PCR System (Applied Biosystems).