In line with our study, a Korean study conducted by Cho et al. [39] found that a large proportion of adolescents with suspected NAFLD, defined as an increased ALT concentration (>30 U/L), had insufficient levels 25(OH)D levels (<20 ng/mL); therefore, adolescents with vitamin D deficiency were considered at increased risk of NAFLD. This evidence concerns the gene GPT and vitamin D deficiency.