The differences in the number of GT repeats affect HO-1 expression: shorter alleles result in the higher basal expression and stronger induction by the HO-1 inducers than the longer alleles [60] and were linked to the risk of various diseases, such as diabetes [61], multiple sclerosis [62], chemotherapy-induced neutropenia [63] and cardiovascular diseases [64, 65]. The gene discussed is HMOX1; the disease is neutropenia.