Maternally inherited diabetes and deafness (MIDD): unusual occult exocrinepancreatic manifestation in an affected German family

The mitochondrial (mt) 3243 DNA mutation is an underlying cause of maternal ly inherited diabetes and deafness (MIDD) syndrome and the syndrome of mito chondrial myopathy, encephalopathy, lactic acidosis and stroke-like episode s (MELAS). We report an affected German MIDD pedigree with maternal lineage over three generations. The index patient, her mother, her maternal aunt a nd her maternal grandmother all suffered from diabetes and premature hearin g loss and were positive on testing for the mt 3243 DNA mutation. The 27-ye ar-old index patient had a history of grand mal seizures. As sequela of abd ominal ultrasound and confirmed by magnetic resonance cholangio-pancreatico graphy, she was diagnosed with chronic pancreatitis with pancreatic calcifi cations and pancreatic duct dilation, although she was completely asymptoma tic and with no signs of steatorrhoea. She did not have gallstones and the common bile duct was normal. A possible etiopathogenic pathway for pancreat itis could be a suppressive effect of the mt 3243 mutation on the oxidative phosphorylation in affected mitochondria. Although pancreatitis and pancre atic dysfunction in association with the mt 3243 mutation, especially in pa tients with comorbidity of MELAS and diabetes, has previously been describe d as a rare manifestation, this case is specific because of the discrepancy of advanced morphological pancreatic alterations and complete lack of panc reatogenic symptoms.