Maternally inherited diabetes and deafness is a rare form of diabetes, accounting for approximately 1% of all diabetes cases. It was , first described in 1992 by van den Ouweland et al in a Dutch family and by Reardon et al in a UK family. This quite heterogeneous syndrome results from an A to G substitution at the conserved position 3243 (m.3243A>G) of the mitochondrial DNA. The age and the mode of presentation of diabetes result in this entity being often misdiagnosed as either type 1 diabetes or type 2 diabetes. 

We present a case of 23 year old Emirati male who was incidentally found to have diabetes following routine pre-employment heath screening.  visit with HbA1c of 12%. He was started on insulin in the local clinic with an initial HbA1c of 12%.  
Two weeks later he presented towas seen at our center for his diabetes management. On examination, hHe was overweight with BMI of 27 kg/m2. He was tested negative for anti-islet humoral markers (anti-GAD, and anti-IA2);  and his insulin secretory reserve was maintained with C-Peptide of 0.631 nmol/L (normal range 0.37-1.47nmol/L) with plasma glucose of 11.6 mmol/L.  Baseline retinal screening demonstrated non-proliferative retinopathy (R1) and maculopathy (M1) with no evidence of other microvascular complications such as microalbuminuria.   
A family history of diabetes was present among maternal relatives.  His maternal uncle and grandmother had diabetes as did his mother.  She had been diagnosed with type 2 diabetes 20twenty years previously and transitioned to insulin for the last 3 years.  Of note she was under In terms of family history, interestingly his mother had over 20 years diagnosis of type 2 diabetes and was managed on insulin for the last 3 years. She had been having ENT follow ups for her hearing problems. 
The clinical suspicion of MIDD was confirmed by the detection of mitochondrial DNA mutation m.3243A>G in patient’s blood sample.  
His mother was also tested positive for mitochondrial DNA mutation m.3243A>G.  
His diabetes is currently managed with sulfonylurea.   and both insulin and Metformin were stopped. Metformin was stopped Cconsidering the potential risk of lactic acidosis metformin has been avoided.   .
Our patient is fully aware the need for insulin in the future considering the course of this mutation.
Although, it is not possible to predict the likely clinical course associated with this mutation due to variation in phenotype, it is important to suspect and confirm the diagnosis by the genetic testing in order to treat the patient optimally, to screen the patient for other clinical features of the syndrome and to look for the affected family members.

Mitochondrial diseases are heterogeneous disorders that result from the genetic derangement of mitochondrial DNA with associated alterations in mitochondrial structure and biochemical properties. Although mitochondrial diseases are usually characterized by encephalomyopathy, multiorgan systems can also be involved. The acronym “MELAS” (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) describes the classic clinical phenotype of the mitochondrial syndromes and is one of a spectrum of phenotypes associated with m.3242A>G mutations.
Although, it is not possible to predict the likely clinical course associated with this mutation due to variation in phenotype, it is important to suspect and confirm the diagnosis by the genetic testing in order to treat the patient optimally, to screen the patient for other clinical features of the syndrome and to look for the affected family members.
Given the high risk of renal complications, tight blood pressure control and ACE-inhibitors are recommended early in the natural history of the disease. Careful monitoring of the cardiac function with a baseline electrocardiogram (ECG) and echocardiogram (ECHO) at the age of 35 or earlier if clinical manifestations exist, is recommended. Annual ECHOs thereafter should also be considered.  
It is advisable that because maternal relatives of patients with MIDD are at high risk of developing diabetes, deafness, renal failure or cardiomyopathy they should be offered long-term follow-up as they are at high risk of developing diabetes, deafness, renal failure and cardiomyopathy. A negative result on a blood test may be falsely reassuring in view of the low heteroplasmy in leucocytes.
This mutation has not been previously described in the United Arab Emirates.  This case highlights the importance of continuing to maintain a high index of suspicion for inherited forms of diabetes.  The high prevalence of diabetes in the Emirati population results in many patients having affected relatives even in the absence of a genetic cause and so careful history taking remains a cornerstone of interaction with our patients.

Maternally inherited diabetes and deafness in an Emirati: challenges of a rare case in a high diabetes prevalence area