Pancytopenia with Chromosomal Fragility: Vitamin B₁₂ Deficiency

Purpose: Pancytopenia in children may have many etiologies. Chromosomal abnormalities with pancytopenia is of particular concern because clonal abnormalities indicate a neoplastic process. We describe three children who had vitamin B₁₂ deficiency and who displayed pancytopenia with multiple chromosomal breaks, rearrangements, and deletions consistent with chromosomal fragility. Severe vitamin B₁₂ deficiency is rare in children and should be considered in the differential diagnosis of a child with pancytopenia, dyserythropoiesis, and multiple chromosomal abnormalities. Patients and Methods: Three children displayed pancytopenia with dyserythropoiesis in the bone marrow. Routine cytogenetic analyses in all three patients were performed and chromosome breakage study was performed on the peripheral blood of one patient after vitamin B₁₂ supplementation. Results: All three patients had severe vitamin B₁₂ deficiency. Spontaneous chromosomal fragility was seen in routine cytogenetic analyses in all three patients. Vitamin B₁₂ supplementation resolved the pancytopenia in all three patients and spontaneous and diepoxybutane-induced breakage rates in chromosomes were well within normal rates after therapy in one patient. Conclusion: The presence of pancytopenia with cytogenetic abnormalities in a child is worrisome. However, careful interpretation of dyserythropoiesis and megaloblastic changes in bone marrow in the aforementioned clinical situation would result in the correct diagnosis of a disorder that is easily cured.