Fazal was 15 months old when he first presented at AFBMTC in July 2017 with transfusion dependent anemia for last 7 months. He was born to a consanguineous marriage and had 3 elder healthy siblings. Examination revealed marked hepatosplenomegaly. He had noisy breathing and according to parents he had nasal obstruction since early infancy. Hearing and vision were intact. CBC showed anemia and thrombocytopenia. His X-ray chest and X-rays of long bones revealed markedly increased bone density with no intramedullary spaces. Bone marrow examination showed thick bony trabeculae and scarce hemopoietic tissue. He was diagnosed with osteopetrosis, the “Marble Bone Disease”. He had received 10 RCC and 16 units of platelets. The patient was HLA matched with his elder sister Areesha and, at the age of 19 months, underwent Allogeneic bone marrow transplantation on 15 Nov 2017. Pre-transplant conditioning was 2 done with Fludarabine (150mg/m) and Busulfan (18mg/kg iv). Bone marrow transplant course was largely uneventful, he achieved engraftment on day+16. However, discharged was delayed till day+43 due to fever caused by very resistant Stenotrophomonas maltophilia. After that, post-transplant course was smooth, tapering of immunosuppression was started at 9 months and stopped by 11 months post-transplant. This November his 12 months post-transplant milestone has been achieved. He has good immune reconstitution and post-transplant chest x-ray showed normal bone density. Contributed By: Dr Muhammad Farhan, FCPS (Clinical Haem)