The clinical presenting symptoms of beta thalassemia include all of the following EXCEPT:

In beta thalassemia, individuals typically exhibit symptoms related to anemia and its effects on the body due to the reduced production of hemoglobin. The correct answer highlights that excessive growth of limbs is not a clinical presenting symptom of this condition.

Failure to thrive by six months, significant anemia, and fatigue and weakness are common symptoms associated with beta thalassemia. Children often show signs of inadequate growth due to the chronic fatigue and weakness stemming from anemia, which results from insufficient functioning hemoglobin and impaired oxygen transport in the bloodstream. Over time, the body’s compensatory mechanisms can lead to splenomegaly and other manifestations.

In contrast, limb growth abnormalities are not typically associated with beta thalassemia. This condition does not induce excessive or abnormal limb growth; rather, the growth may be stunted due to the overall health impact and the body's inability to produce sufficient red blood cells.