Maternally inherited diabetes and deafness (MIDD)

• caused by a mutation in mitochondrial DNA (3243 tRNA)
  • mitochondrial DNA is contributed to the embryo by the oocyte and not by spermatozoa, and therefore this disease is inherited from maternal family members only
    
    
• diabetes is a non insulin dependent type that usually presents before the age of 40 years
  • due to a defect in beta cell function with normal insulin sensitivity
  • associated deafness is sensorineural and develops in most of the diabetic subjects
    • hearing loss is variable
      • of these diabetic patients carrying the mitochondrial DNA mutation at position 3243, 75% experience sensorineural hearing loss
      • associated hearing loss with diabetes is typically more common and more quickly declining in men than in women
        
        
• MIDD may have other multi-organ features: for example, elevated serum lactate, neuromuscular and cardiac problems, pigmented retinopathy, and nephropathy with proteinuria

Reference:

• Murphy R et al. Clinical features, diagnosis and management of maternally inherited diabetes and deafness (MIDD) associated with the 3243A>G mitochondrial point mutation. Diabet. Med. 2008, 25(4),383-99.