We found that serum levels of S100A9 positively correlated with NAS and histologic features of hepatic steatosis and lobular inflammation (r = 0.80, 0.64, and 0.84, respectively, P < 0.001; Fig 5A), indicating that it is a reliable marker for the severity of hepatic histologic features. The gene discussed is S100A9; the disease is neonatal abstinence syndrome.