Mitochondrial DNA deletions detected by Multiplex Ligation-dependent Probe Amplification

Abstract

The genetic diagnosis algorithm for mitochondrial (mt) diseases starts looking for deletions and common mutations in mtDNA. MtDNA’s special features, such as large and variable genome copies, heteroplasmy, polymorphisms, and its duplication in the nuclear genome as pseudogenes (NUMTs), make it vulnerable to diagnostic misleading interpretations. Multiplex Ligation-dependent Probe Amplification (MLPA) is used to detect copy number variations in nuclear genes and its application on mtDNA has not been widely spread. We report three Kearns Sayre Syndrome patients and one Chronic Progressive External Ophthalmoplegia adult, whose diagnostic mtDNA deletions were detected by MLPA using a very low amount of DNA. This managed to “dilute” the NUMT interference as well as enhance MLPA’s efficiency. By this report, we conclude that when MLPA is performed upon a reduced amount of DNA, it can detect effectively mtDNA deletions. We propose MLPA as a possible first step method in the diagnosis of mt diseases.

• Chronic progressive external ophthalmoplegia
• copy number changes
• diagnosis
• Kearns Sayre Syndrome
• mitochondrial disease
• NUMTs

Acknowledgements

The authors thank Columbia University for the assistance with Long-range PCR, Southern blot, and Sequencing analysis free of charge. They also thank the Inborn Errors of Metabolism and Genetics laboratory from Garrahan Hospital and Ramos Mejía Hospital, for metabolic work up and for extracting patient’s leukocyte’s DNA.

Declaration of interest

The authors report that they have no conflicts of interests. The authors did not count with any funding source for the execution of the study nor preparation of the manuscript.