A study on asthma in adolescents investigated retinol-binding protein (RBP4) and plasminogen activator inhibitor (PAI-1) and found that RBP4 was useful in predicting non-allergic asthma in adolescents with obesity (Leija-Martinez et al., 2021). The gene discussed is RBP4; the disease is obesity due to melanocortin 4 receptor deficiency.