Hemoglobin H disease is caused by deletion of-

Moderate microcytic hypochromic anemia.People with hemoglobin H disease have a variable phenotype that can range from mild symptoms to those similar to thalassemia major. Hemoglobin H disease is a type of alpha thalassemia caused by impaired production of three of the four alpha globins, coded by genes HBA1 and HBA2 Exam preparatory manual for UGs by Ramdas Nayak Paage no:273 Ref Robbins 9/e 413