MicroRNAs (miRNAs) are 19-24 nucleotide non-coding ribonucleic acids binding DNA or RNA and controlling gene expression via mRNA degradation or its transcription inhibition. Erythropoies is a multi step differentiation process of erythroid progenitors to nucleate red blood cells. Maturation, proliferation and differentiation of red blood cells is affected by erythroid factors, signaling pathways in niche of hematopoietic cells, transcription factors as well as miRNAs. Expression of different types of miRNAs during erythroid development provides a background for the study of these molecules to control erythroid differentiation and maturation as well as their use as diagnostic and prognostic markers to treat erythroid disorders like thalassemia, sickle cell disease and erythrocyte enzyme deficiencies. In this paper, with reference to biosynthesis of miRNAs, their function in normal and anemic erythropoiesis has been investigated. The target molecule of each of these miRNAs has been cited in an attempt to elucidate their role in erythropoiesis.

β-Thalassemia is a genetic disorder with a continuum of mild to severe clinical manifestations and requirement of transfusion at different stages of life. The cause(s) of this variety is not clear but genetic alterations could be a potential factor. In this review, the correlation between polymorphisms and different clinical manifestations, including the need for transfusion, was investigated. Relevant articles published in pubmed database from 1982 onwards were studied and compiled. The articles all contained the keywords β-thalassemia, genetic modifiers, and mutations. Certain polymorphisms and mutations could dictate the severity of symptoms as well as their onset. A significant number of the mentioned genetic alterations appear in beta-globin gene cluster and affect gamma chain. Therefore, hemoglobin F production rate is increased and can affect thalassemia symptoms and can relieve β-thalassemia symptoms. A number of polymorphisms in catalase and glutathione S transferase genes have also been shown to modify the severity of disease and response to treatment. Knowledge of these mutations and polymorphisms can provide an insight into the prognosis for individual patients, especially in young ages or before birth to take proper measures in advance and eventually ameliorate the symptoms in the long run.

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Chronic lymphoid leukemia (CLL) is a lymphoproliferative disorder with clonal proliferation and accumulation of mature B-cells in BM, peripheral blood, and secondary lymphoid organs. Most patients show del(13q), del(11q), +12, del(17p), and del(6q) genetic abnormalities, and chromosomal translocation has been rarely reported in them. We report a 43-year-old man diagnosed with CLL with two additional marker chromosome segments of unknown origin 48, XY, +mar, + mar analyzed by G-banded karyotype analysis. Peripheral blood smear revealed markedly increased white blood cell count (WBC, 84,000/mm 3 ) with predominance of lymphoid cells with dense chromatin. To our knowledge, this chromosomal abnormality in CLL has not been previously described, and we report it for the first time from Iran.