Heterogeneity of six children and their mothers with mitochondrial DNA 3243 A>G mutation

Abstract

To study the clinical, biochemical, and genetic heterogeneity of six Chinese patients and their mothers with the 3243 A>G mutation, six patients (ranging from 5 to 11 years) were hospitalized. All the mothers were healthy. Mitochondrial respiratory chain enzyme activities were determined by spectrophotometry. Mitochondrial gene was analyzed in all patients. Six core pedigrees were investigated. Two patients had mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome and one had Leigh syndrome. The common initial symptoms were headache, vomiting, blurred vision, and epilepsy. m.3243A>G mutation was detected in all patients and their mothers. The mutation loads ranged from 43.6% to 58% and those of their mothers ranged from 14.1% to 28.6%. Varied respiratory chain deficiencies were observed in all patients and two mothers. m.3243A>G mutation can result in a wide spectrum of respiratory chain complex deficiencies. Mitochondrial DNA mutation detected in blood may be likely to transmit to offspring, and the mutation load may increase.

Keywords::

• Mitochondrial disorders
• respiratory chain complex deficiency
• mitochondrial DNA
• 3243A>G mutation

Acknowledgements

The authors are grateful for the technical supports and collaboration of Dr Weiyue Gu from Bio Road Biotech Co., Ltd, Beijing, P.R. China.

Declaration of interest: This work was supported by the National Nature Science Foundation of China (No. 30872794), the 12th Five-year Plan National Key Technology R & D Program from the Ministry of Science and Technology (2012BAI09B04) and Beijing Nature Science Foundation (No. 7081002). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.