The amino acid Leucine improves anemia and developmental defects in DBA zebrafish and mouse models and patients.258,259l-leucine stimulates mRNA translation through activation of the mTOR (the mammalian target of rapamycin) pathway, which regulates cap-dependent translation of TOP mRNAs to synthesize proteins involved in the translational apparatus.259,260 The efficacy of l-leucine for the treatment of transfusion-dependent DBA is being evaluated in Phase I/II clinical trials (NCT01362595, NCT02386267, https://clinicaltrials.gov/ct2/home). This evidence concerns the gene MTOR and anemia (phenotype).