Severe atrophy of the cerebellum on magnetic resonance imaging in a Chinese patient with maternally inherited diabetes and deafness with the A3243G mitochondrial DNA mutation

Maternally inherited diabetes and deafness (MIDD) is a rare form of diabetes with a maternal transmission and sensorineural hearing loss. Neuroradiological abnormality manifestations have been relatively rarely reported in MIDD patients. In this report, we will describe the clinical features, genetic alterations, and neuroradiological alterations in a Chinese patient with MIDD. We conducted a series of clinical examinations in the patient, including beta cell function, cognitive function tests, and magnetic resonance imaging (MRI) of the brain. The A3243G mitochondrial DNA (mtDNA) mutation in blood cells was assessed by direct sequencing analysis, and the proportions of mutant mtDNA was also analyzed. The patient exhibited the clinical features of early onset of diabetes with progressive insulin secretory defect, sensorineural hearing loss, and maternal history of diabetes and deafness. He had slightly impaired cognitive function. A brain MRI revealed severe atrophy of the cerebellum. Analysis of mtDNA revealed the A3243G mutation, with the proportion of mutant mtDNA of 15 % in leukocytes. This case extends the phenotype of the tRNA^{Leu [UUR]} A3243G mtDNA mutation.