A 5-year-old male presented to Paediatric OPD with chief complaints of weakness, breathlessness and pain abdomen for one week. Lab investigations revealed Hb- 3.5gm/dl, TLC-4900/cmm, RBC count- 4.8 million/cmm, MCV – 58 fl & platelets count- 5 lakh/cmm. Patient has received multiple blood transfusions in the past. On examination, facial deformity and massive splenomegaly were found. X-ray skull revealed crew cut appearance. a. What is most likely diagnosis? b. Write its mode of inheritance and actionathogenesis. c. Write its laboratory diagnosis.