DIABETES WITH THE 3243-MITOCHONDRIAL TRNA(LEU(UUR)) MUTATION - CHARACTERISTIC NEUROIMAGING FINDINGS

OBJECTIVE - To investigate the basis of central nervous system dysfunc tion in diabetes associated with the 3243 mitochondrial tRNA mutation, we studied neuroimaging findings in patients with this disease. RESEA RCH DESIGN AND METHODS - We screened 205 diabetic patients. Those pati ents who had the 3243 mutation in leukocytes or muscle were enrolled. All the subjects underwent computed tomography (CT), magnetic resonanc e imaging (MRI), magnetic resonance angiography (MRA), and N-isopropyl -p-[I-123]iodoamphetamine ([I-123]IMP) single-photon emission computed tomography (SPECT) of the brain. RESULTS - None of the nine subjects with the 3243 mutation had the typical clinical picture of mitochondri al myopathy, encephalopathy, lactic acidosis, and stroke-like episodes , and none had neurological focal signs. CT or MRI revealed diffuse br ain atrophy in three patients (33%) and cerebellar atrophy in one (11% ). Abnormal high intensity areas were observed on MRI in five patients (56%). The overall prevalence of brain abnormalities was 56% (5 of 9) on CT and 78% (7 of 9) on MRI scans. MRA revealed no stenotic lesions . SPECT showed reduced accumulation of [I-123]IMP in the right or left parieto-occipital region in eight patients (89%). CONCLUSIONS - Reduc ed accumulation of [I-123]IMP in the parieto-occipital cortex was foun d in a high proportion of our subjects on SPECT. This imaging finding might be characteristic of diabetes associated with the 3243 mitochond rial tRNA mutation and may be a sign of latent central nervous system dysfunction.