Final answer:
Pernicious anemia is characterized by macrocytic, megaloblastic anemia without neurologic symptoms, and is the result of a vitamin B12 or folate absorption deficiency, not a dietary lack.
Step-by-step explanation:
The condition characterized by macrocytic, megaloblastic anemia without neurologic symptoms is known as pernicious anemia. This type of anemia involves the deficiency of vitamin B12 and/or folate, usually due to poor absorption of these nutrients rather than a lack of intake. Despite presenting with macrocytic, megaloblastic anemia, pernicious anemia typically lacks associated neurologic symptoms, which distinguishes it from other forms of anemia that are due to B12 deficiency.
Iron deficiency anemia, sickle cell anemia, and thalassemia present with different types of anemia or affect the red blood cells (RBCs) differently. Sickle cell anemia and thalassemia are inherited conditions that usually lead to normocytic or microcytic anemia rather than macrocytic, while iron deficiency anemia results in microcytic anemia because of insufficient iron to produce heme. Hence, the correct answer to the question is pernicious anemia.