GDF15 and metabolic dysfunction-associated steatotic liver disease: Finally, we found that also in our subset of 15 patients with MASLD, the hepatic expression of the COL1A1 and COL3A1 transcripts was increased in the liver of children with MASH compared to the liver of those without MASH and that the increased expression of the GDF15 gene was positively correlated with that of the two profibrogenic genes (Figure 5A–C).