Final answer:
The most common congenital cause of aplastic anemia is Fanconi anemia. Aplastic anemia results from a deficiency of RBC stem cells which can be caused by genetic conditions like Fanconi anemia or acquired through environmental exposures such as radiation or certain medications.
Step-by-step explanation:
The most common congenital cause of aplastic anemia is Fanconi anemia, which is an inherited disorder that leads to bone marrow failure. Aplastic anemia is characterized by a deficiency in the number of red blood cell (RBC) stem cells, and in the case of Fanconi anemia, it is a result of a genetic defect affecting DNA repair. Exposure to radiation, certain medications, chemotherapy, or infections can trigger aplastic anemia as well, but these causes are not congenital. Individuals with aplastic anemia have reduced levels of red blood cells, white blood cells, and platelets. Blood cells are usually produced in the bone marrow, and in aplastic anemia, the bone marrow's stem cells that are responsible for creating these cells are either absent or not functioning properly. Treating aplastic anemia can sometimes involve "rebooting" the immune system, which can include treatments such as immunosuppressive therapy or a bone marrow transplant to restore healthy bone marrow function.