Deafness as a clue to the genetic transmission of diabetes: a case report, commentary, and recommendations

Czech version

Authors: Jozef Lacka ¹; Barbora Lacková ²
Authors‘ workplace: JAL, s. r. o., Trnava ¹; Interní oddělení, ambulance obezitologie, Nemocnice Rudolfa a Stefanie Benešov, a. s., Nemocnice Středočeského kraje ²
Published in: Diab Obez 2026; 26(1): 42-46
Category: Case studies

Overview

Maternally inherited diabetes and deafness (MIDD) is a rare form of monogenic diabetes caused by mutations in mitochondrial DNA, most commonly m.3243A>G, characterized by maternal inheritance and the combination of diabetes and sensorineural hearing loss. We present a case of a female patient whose diabetes was initially classified as type 2 diabetes mellitus following gestational diabetes. Recurrent spontaneous miscarriages, a family history of hearing impairment, and the occurrence of epilepsy in her offspring raised suspicion of a mitochondrial disorder. Molecular genetic testing confirmed the presence of the pathogenic m.3243A>G variant in a heteroplasmic state, establishing the diagnosis of MIDD. The case report highlights the importance of a thorough family history and the need for differential diagnostic consideration of monogenic forms of diabetes. From a therapeutic perspective, it is important to avoid medications that interfere with mitochondrial metabolism, particularly metformin due to the risk of lactic acidosis; treatment with sulfonylurea derivatives is also not appropriate. Suitable alternatives include therapy with GLP-1 receptor agonists or insulin. Early diagnosis of MIDD enables appropriate treatment selection, reduces the risk of complications, and allows targeted screening of maternal relatives.

Keywords:

sensorineural hearing loss – maternally inherited diabetes and deafness (MIDD) – mitochondrial diabetes

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