Schwachman-Diamond Syndrome is characterized by which of the following?

Schwachman-Diamond Syndrome is primarily characterized by pancreatic insufficiency. This condition arises because the pancreas does not produce enough digestive enzymes, which can lead to difficulties in digesting and absorbing nutrients effectively. Individuals with this syndrome may experience symptoms such as failure to thrive, poor growth, and gastrointestinal issues due to this pancreatic dysfunction.

While hematological malignancies and neurological deficits can occur in some patients with Schwachman-Diamond Syndrome, they are not defining characteristics of the syndrome itself. Excessive weight gain is generally not associated with this condition due to the malabsorption that results from pancreatic insufficiency. Therefore, pancreatic insufficiency stands out as the hallmark feature of Schwachman-Diamond Syndrome, making it the correct answer in this context.