SAT084 Maternally Inherited Diabetes With Deafness: A Rare And Challenging Diagnosis Of Diabetes

Disclosure: K. Cuan: None. I.R. Bass: None. Introduction: Maternally inherited diabetes with deafness (MIDD) is a rare mitochondrial disease with variable phenotypic expression characterized by a defect in insulin secretion and sensorineural hearing loss. Other potential features of MIDD include proximal myopathy, macular retinal dystrophy, and renal focal segmental glomerulosclerosis. Mitochondrial diseases are difficult to recognize given their heterogeneous presentation, however accurate diagnosis of MIDD is important as there are implications for management. DESCRIPTION: A 38-year-old adopted woman with previously diagnosed type 1 diabetes (T1DM), congenital deafness, and chronic kidney disease presented to our endocrinology clinic with concerns for difficulty controlling her blood glucose levels. She was diagnosed with T1DM at age 21 based on age and normal body habitus and was started on insulin. Due to insurance issues, she discontinued insulin use for several years and her diabetes was poorly controlled during that time, however, she never experienced diabetic ketoacidosis (DKA). Upon resuming insulin, she experienced multiple unpredictable episodes of hypoglycemia and subsequently self-discontinued insulin and presented 8 months later for further care. Past history was notable for muscle weakness with walking upstairs and vision loss in her left eye, which led to a diagnosis of retinopathy in her early twenties. Her family history was unavailable as she was adopted. Her physical exam was significant for a normal body mass index of 24. Labs showed a hemoglobin A1C of 10.8% and detectable c-peptide, 2.7 ng/mL (1.1-4.4 ng/mL) with a glucose of 192mg/dL. Glutamic acid decarboxylase, zinc transporter 8, IA-2 and islet-cell antibodies were all negative. Her creatinine was 1.23 ng/dL with a severely increased microalbumin to creatinine ratio (638, 0-29 mg/g). In view of her congenital deafness, non-diabetic retinopathy, absence of DKA while off insulin, negative antibody testing, and chronic kidney disease, mitochondrial diabetes was considered. She was referred to a geneticist for mitochondrial genome sequencing, of which the results are pending. Dietary modification and oral agents were recommended for her diabetes management, rather than insulin therapy. DISCUSSION: MIDD can be challenging to diagnose and patients may be incorrectly labeled as having type 1 diabetes. The presence of maternal transmission can aid in the diagnosis of MIDD, however, our patient was adopted and this information is unavailable. Additionally, retinal and renal features of MIDD can be misconstrued as microvascular complications of diabetes. In patients with deafness and poorly controlled diabetes with negative antibody testing, MIDD should be considered as an alternative diagnosis. MIDD can be managed with dietary modification, oral agents, and insulin if appropriate. Presentation: Saturday, June 17, 2023