Maternally Inherited Diabetes and Deafness (MIDD) – Atypical Clinical Diabetes Features Leading to the Diagnosis

Maternally inherited diabetes and deafness (MIDD) syndrome refers to a rarely diagnosed disorder caused by pathogenic variants in mtDNA. It was first identified in 1992 and, to date, is considered underdiagnosed because of misclassification to type 1 or type 2 diabetes mellitus. MIDD reflects a multisystem metabolic syndrome commonly resulting in insulin-requiring diabetes and sensorineural deafness but can also lead to a broad range of other manifestations. The spectrum of pathology differs among individuals, likely because of varied degrees of heteroplasmy associated with mtDNA. Heteroplasmy also creates diagnostic difficulties, with a high index of suspicion required to diagnose MIDD in some cases. Here, we review a patient with MIDD who presented with an atypical clinical diabetes picture, additionally documenting his pedigree. To our knowledge, this is the first Cypriot reported with MIDD.