Micromegakarycytes in a patient with partial deletion of the long arm of chromosome 11 del (ll)(q24.2qter)] and chronic thrombocytopenic purpura

Thrombocytopenia or pancytopenia is frequently reported in patients with partial 11q deletion but there are no reports on bone marrow morphology of these patients. We report on a patient with partial deletion of the long arm of chromosome 11 [del(11) (q24.2qter)] and its classical clinical manifestations including chronic thrombocytopenic purpura in whom micromegakaryocytes were found in the bone marrow aspirate. This is the first report of the presence of micromegakaryocytes in the bone marrow of a patient with 11q deletion. Accurate examination of the bone marrow of other patients with the 11q deletion may clarify whether the observation of micromegakaryocytes is common in these patients. Micromegakaryocytes may indicate a defect of development. Two genes for two DNA binding proteins that are likely to be involved in hematopoiesis map in the 11q region: Ets-1, that maps to 11q24, close to D11S912, and the nuclear-factor-related-kB gene that maps to 11q24-q25. It is possible that these genes, when present in only one copy, result in thrombocytopenia or pancytopenia as observed in this patient.