Deletional HPFH and δβ‐thalassemia (deletional HPFH/δβ‐thalassemia) is a rare inherited condition that is characterized by increased Hb F, which results from deletions in the upstream silencer region of the γ‐globin genes or upregulation of the γ‐globin genes (Sankaran, Xu, & Orkin, 2010), as there is no competition from the expression of β‐ and δ‐globin genes. The gene discussed is GSTM1; the disease is thalassemia.