Initial screening for the diagnosis of NAFLD includes the exclusion of secondary causes of liver steatosis and the use of two times the sex-specific alanine aminotransferase (ALT) (≥ 52 U/L for boys and ≥ 44 U/L for girls) in children ≥ 10 years, with body mass index (BMI) ≥ 85th and < 94th (overweight) or ≥ 95th percentile (obese), with a sensitivity of 88%, but low specificity of 26% [1, 2]. This evidence concerns the gene GPT and Hepatic steatosis.