Niemann-Pick disease type C: unique 2-deoxy-2[¹⁸F] fluoro-D-glucose PET abnormality.

Serial 2-deoxy-2[(18)F]fluoro-D-glucose positron emission tomography was performed in identical twins with Niemann-Pick disease type C. Two such scans, performed at ages 4 and 6 years, revealed a characteristic, unique pattern of brain metabolic abnormality. Whereas the first scans indicated mild, diffuse cortical hypometabolism, most pronounced in the medial frontal cortex, the repeated scans in both twins revealed a unique pattern consisting of severe hypometabolism of the frontal cortex bilaterally, particularly involving medial and inferior frontal regions, and hypometabolism in the bilateral parietal and temporal cortex. In the parietal cortex, lateral and medial aspects were most severely affected, with some sparing of the intermediate parietal region. This progression of brain hypometabolism between two positron emission tomography studies was associated with clinical and neurologic deterioration. This distinctive brain metabolic pattern, which we have observed in no other condition, may constitute a "biomarker" to assess neurologic progression and possible treatment responses in children with Niemann-Pick disease type C, because magnetic resonance imaging findings are either normal at earlier stages or demonstrate only nonspecific changes.