Additionally, a zebrafish model of classic galactosemia (CG) (galtKO), a hereditary disease of galactose metabolism caused by deficiency in galactose-1-phosphate:uridylyltransferase (GALT) activity, has been treated with human GALT mRNA by one-cell stage injection, resulting in enzyme activity and a decrease in the accumulated metabolites [11]. The gene discussed is GALT; the disease is galactosemia.