Other erythroid-specific enhancers have also been found in the genomic regions of GATA–1, stem cell leukemia (SCL), L-type pyruvate kinase and 5-aminolevulinate synthase 2 (ALAS2) genes [17-20], which may contribute to the restricted expression of these genes in the erythroid lineage. Here, ALAS2 is linked to acute leukemia.