In an analysis of serum lipidomes of a cohort of 535 patients (steatosis, n = 182; NASH, n = 183), our group identified a serum lipidomic signature associated with Mat1a-KO mice that subclassified this cohort into two main subtypes: a first subtype showing a serum lipidomic profile similar to that observed in Mat1a-KO mice (M-subtype) that was present in 49% of the patients and a second subtype showing a different profile (non-M subtype) [13]. This evidence concerns the gene MAT1A and metabolic dysfunction-associated steatohepatitis.