<prompt> Answer this question truthfullyWhat is the name of the non-megaloblastic macrocytic anemia that is characterized by rapid onset of anemia within the first year of life?  <response>: <reason> Diamond-Blackfan anemia also known as congenital pure red cell aplasia or congenital hypoplastic anemia is the non-megaloblastic macrocytic anemia that presents with rapid-onset anemia within the first year of life. This rare genetic disorder is caused by a defect in the bone marrows ability to produce red blood cells, leading to severe anemia and other symptoms. Diamond-Blackfan anemia is typically diagnosed in infancy or early childhood and is treated with blood transfusions, corticosteroids, and other supportive therapies. 