Myelofibrosis associated with rickets in a child with down syndrome

To the Editor: Rickets is an illness which is seen in childhood due to the lack of vitamin D. Myelofibrosis is rarely associated with rickets. Say and Berkel [1] described the first case of rickets associated with myelofibrosis. All the reported cases are in infanthood [1–13]. We diagnosed and treated myelofibrosis associated with rickets in a 10-year-old male with Down syndrome. The patient presented with fever, thrombocytopenia, and anemia. He had Down syndrome which was genetically proven. His weight (14 kg), height (110 cm), and head circumference (48 cm) were below the third percentile. He had massive hepatosplenomegaly, rachitic rosaries, widened wrists, and ankles. He could sit but not walk. Hemoglobin level was 5.4 g/dl, white blood cell count was 5.6 10/L and platelet count was 26 10/L. Bone marrow aspiration demonstrated decreased erythroid, myeloid and megakaryocytic lineage, and normal myeloid/erythroid ratio. There were no signs of abnormal maturation and myelodysplasia. Leukemic infiltration was not observed. Serum calcium was 5.7 mg/dl (normal range 8.1–10.7), phosphorus 0.73 mg/dl (normal range 2.3–4.7), alkaline phosphatases 587 U/L (normal range 95–280), 25-hydroxy-vitamin D3 level 5 mg/L (normal range 30– 80). A diagnosis of rickets related to lack of D vitamin was made. Secondary hyperparathyroidism was suspected since parathyroid