HbH disease is characterized by which of the following?

HbH disease is a form of alpha-thalassemia that results from the deletion or dysfunction of multiple alpha-globin genes, leading to an imbalance in globin chain production. In this condition, there is a significant production of HbH, which is an abnormal hemoglobin composed of four beta-globin chains, and HbBarts, which is composed of four gamma-globin chains.

The elevated levels of HbH and HbBarts are diagnostic of HbH disease and are indicative of the body’s attempt to compensate for the lack of adequate alpha-globin chains. This imbalance can lead to microcytic anemia since the presence of abnormal hemoglobin types affects the efficiency of oxygen transport in the blood. Recognizing the presence of these hemoglobins is critical in diagnosing the condition and distinguishing it from other hemoglobinopathies.

In addition to the presence of HbH and HbBarts, individuals with HbH disease typically have lower levels of fetal hemoglobin and an absence of normal adult hemoglobin A. The other conditions mentioned, such as excessive iron deposition and normal hemoglobin levels, do not correlate with the pathology of HbH disease. Thus, the primary characterization of this disease is indeed the high levels of HbH and HbBarts