Our pilot study suggests that the presence of both obesity and persistent elevated serum ALT levels is associated with increased fecal SCFA levels and the abundance of SCFA-producing bacteria, particularly Roseburia. In addition, although increased fecal SCFA concentrations were associated with higher dietary fiber intake and Roseburia abundance, future studies in larger samples, measuring fecal and circulating SCFA concentrations, are required to clarify SCFA role in metabolic diseases. The gene discussed is GPT; the disease is obesity due to melanocortin 4 receptor deficiency.