As you are all aware, Diamond Blackfan anemia is referred to as a macrocyctic anemia.  The term macrocytosis, meaning large cells, relates to the increased size of red blood cells in patients with DBA. An explanation for this phenomenon may reside in a recent manuscript published by Sankaran and colleagues in the journal, Genes and Development ¹.

Before exploring the Sankaran paper, I think it is worthwhile to provide a little background on macrocytic anemia.  In this regard, it is important to point out that DBA is not the only macrocytic anemia.  In fact, macrocytosis is observed in the megaloblastic anemias which are commonly encountered by the medical community.  Two causes of megaloblastic anemia are deficiencies of folic acid and vitamin B12.  The increased size of red blood cells in individuals with folic acid deficiency is relatively easy to envision, so I thought I would begin there.  

Folic acid plays an important role in intermediary metabolism; the chemical transformations that occur within cells.  Specifically, folic acid plays a role in reactions where single carbon units are used to build larger, more complex molecules.  Some of these more complex molecules are the nucleotides which serve as precursors for the synthesis of DNA and RNA.  Thus, individuals deficient in folic acid have a problem making copies of their DNA, a critical component of cell division.   DNA needs to be copied so new cells created when cells divide will have the necessary genetic blueprint for them to fulfill their functions within the body.  Another component of cell division is cell growth.  If a cell were to divide without growth, the cells would get smaller and smaller until there would be nothing left.   Thus, cell growth and division go hand in hand as cells multiply within the body.   

Under most circumstances that is.