Whole mitochondrial genome screening of a family with maternally inherited diabetes and deafness (MIDD) associated with retinopathy: A putative haplotype associated to MIDD and a novel MT-CO2 m.8241T>G mutation

J Diabetes Complications. 2017 Jan;31(1):253-259. doi: 10.1016/j.jdiacomp.2016.06.028. Epub 2016 Jul 1.


Mitochondrial diseases are a clinically heterogeneous group of disorders that arise as a result of dysfunction of the mitochondrial respiratory chain. They can be caused by mutations in both nuclear and mitochondrial DNA. In fact, mitochondrial DNA (mtDNA) defects are known to be associated with a large spectrum of human diseases and patients might present wide range of clinical features with various combinations. Our study reported a Tunisian family with clinical features of maternally inherited diabetes and deafness (MIDD). Accordingly, we performed a whole mitochondrial genome mutational analysis, results revealed a haplotype composed by "A750G, A1438G, G8860A, T12705, T14766C and T16519C", in homoplasmic state, in the mother and transmitted to her daughter and her son. The patient with MIDD2 and retinopathy presented, in addition to this haplotype associated to the MIDD, two de novo variations including a novel one m.8241T>G (p. F219C) in MT-CO2 gene and a known one m.13276G>A (p. M314V) in MT-ND5 gene. The coexistence of these two mutations could explain the retinopathy observed in this patient.

Keywords: Family; Haplotype; Mitochondrial DNA mutation; Mitochondrial inherited diabetes and deafness; Retinopathy.

MeSH terms

  • Adult
  • Amino Acid Substitution
  • DNA Mutational Analysis
  • DNA, Mitochondrial*
  • Databases, Protein
  • Deafness / blood
  • Deafness / complications
  • Deafness / genetics*
  • Deafness / metabolism
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / complications
  • Diabetes Mellitus, Type 2 / genetics*
  • Diabetes Mellitus, Type 2 / metabolism
  • Diabetic Retinopathy / blood
  • Diabetic Retinopathy / complications
  • Diabetic Retinopathy / genetics*
  • Diabetic Retinopathy / metabolism
  • Electron Transport Complex I / chemistry
  • Electron Transport Complex I / genetics*
  • Electron Transport Complex I / metabolism
  • Electron Transport Complex IV / chemistry
  • Electron Transport Complex IV / genetics*
  • Electron Transport Complex IV / metabolism
  • Family Health
  • Female
  • Humans
  • Male
  • Mitochondrial Diseases / blood
  • Mitochondrial Diseases / complications
  • Mitochondrial Diseases / genetics*
  • Mitochondrial Diseases / metabolism
  • Mitochondrial Proteins / chemistry
  • Mitochondrial Proteins / genetics*
  • Mitochondrial Proteins / metabolism
  • Models, Molecular*
  • Obesity / blood
  • Obesity / complications
  • Obesity / genetics
  • Obesity / metabolism
  • Pedigree
  • Point Mutation*
  • Protein Conformation
  • Structural Homology, Protein
  • Tunisia


  • DNA, Mitochondrial
  • Mitochondrial Proteins
  • MT-ND5 protein, human
  • cytochrome C oxidase subunit II
  • Electron Transport Complex IV
  • Electron Transport Complex I

Supplementary concepts

  • Noninsulin-dependent diabetes mellitus with deafness