Cerebral glucose metabolism in type I alpha-N-acetylgalactosaminidase deficiency: An infantile neuroaxonal dystrophy

Cerebral glucose metabolism was investigated in a 4.8-year-old boy with alp ha-N-acetylgalactosaminidase deficiency using 2-[F-18]fluoro-2-deoxy-D-gluc ose and positron emission tomography (PET). In comparison to normal values for age, the overall cerebral glucose metabolism was reduced and the region al cerebral glucose metabolism was decreased in proportion to the degree of atrophy. In the supratentorial cortical regions, the hypometabolism was as ymmetric. However, the level of regional cerebral glucose metabolism in all cortical regions excluded a persistent vegetative state. In the lentiform nucleus and the head of the caudate, comparatively increased regional cereb ral glucose metabolism was documented, similar to findings in neurodegenera tive disorders with active epilepsy. In contrast, the infratentorial struct ures (cerebellar hemispheres, brain stem, mesencephalon, and hypothalamus), which are predominantly affected by the atrophic process, showed distinct and symmetric hypometabolism. Thus, the 2-[F-18]-fluoro-2-deoxy-D-glucose P ET scans provided additional insight into and correlation of the functional and structural disturbances in type I alpha-N-acetylgalactosaminidase defi ciency, in addition to documenting the hypometabolism due to brain atrophy.