A 3-year clinical follow-up of adult patients with 3243A>G in mitochondrial DNA

Neurology. 2006 May 23;66(10):1470-5. doi: 10.1212/01.wnl.0000216136.61640.79.


Objective: To follow the clinical course of patients with the mitochondrial DNA mutation 3243A>G for 3 years.

Methods: Thirty-three adult patients with the 3243A>G mutation entered a 3-year follow-up study. They were clinically evaluated annually, audiometry was performed, and samples were drawn for the analysis of blood chemistry and mutation heteroplasmy in leukocytes. Holter recording was performed three times during the follow-up and echocardiography, neuropsychological assessment, and quantitative EEG and brain imaging conducted at entry and after 3 years.

Results: The incidence of new neurologic events was low during the 3-year follow-up. Sensorineural hearing impairment (SNHI) progressed, left ventricular wall thickness increased, mean alpha frequency in the occipital and parietal regions decreased, and the severity of disease index (modified Rankin score) progressed significantly. The rate of SNHI progression correlated with mutation heteroplasmy in muscle. The increase in left ventricular wall thickness was seen almost exclusively in diabetic patients. Seven patients died during the follow-up, and they were generally more severely affected than those who survived.

Conclusions: Significant changes in the severity of disease, sensorineural hearing impairment, left ventricular hypertrophy, and quantitative EEG were seen in adult patients with 3243A>G during the 3-year follow-up.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alleles
  • Blood Glucose / analysis
  • Cognition Disorders / genetics
  • DNA, Mitochondrial / genetics*
  • Diabetes Mellitus / blood
  • Diabetes Mellitus / genetics
  • Disease Progression
  • Electrocardiography, Ambulatory
  • Electroencephalography
  • Female
  • Finland / epidemiology
  • Follow-Up Studies
  • Hearing Loss, Sensorineural / genetics
  • Humans
  • Hypertrophy, Left Ventricular / diagnostic imaging
  • Hypertrophy, Left Ventricular / genetics
  • Lactates / blood
  • MELAS Syndrome / genetics*
  • MELAS Syndrome / mortality
  • Male
  • Middle Aged
  • Mitochondria, Muscle / metabolism
  • Mosaicism
  • Neuropsychological Tests
  • Point Mutation*
  • Pyruvates / blood
  • Ultrasonography


  • Blood Glucose
  • DNA, Mitochondrial
  • Lactates
  • Pyruvates