Molecular Diagnosis for Mitochondrial DNA Aberrations in Chronic Progressive External Ophthalmoplegia

ABSTRACT

PURPOSE: To evaluate the spectrum of mitochondrial DNA (mtDNA) aberrations in patients with suspected chronic progressive external ophthalmoplegia (CPEO) and to establish the molecular diagnostic method for CPEO in Koreans. METHODS: We performed mtDNA analyses for single deletions with long-range PCR and direct sequencing, and for the nine important point mutations including 3243A>G and 8344A>G with PCR/RFLP in muscles, bloods and paraffin-embedded muscle sections of 16 Korean patients with suspected CPEO. RESULTS: Three novel single mtDNA deletions were identified in three patients' muscles 3159bp deletion from np 6657 to np 9815, 7591bp from np 8429 to np 16019, and 6191bp from np 7799 to np 13989. In addition, multiple mtDNA deletions were found in one patient. None of the blood specimen had mtDNA deletions even in the patients with mtDNA deletion in muscle. All single deletion junctions were flanked by direct repeats of 6-8 bp. None of the nine mtDNA point mutations were found in muscles, bloods or paraffin-embedded muscle sections. CONCLUSIONS: We identified three novel single deletions by mtDNA analyses in the muscles of 3 patients with CPEO. However, point mutations were not found. Furthermore, we established a molecular diagnostic method for CPEO in Korea. Long-range PCR and direct sequencing of the muscles were appropriate as a molecular diagnostic method for CPEO in Koreans.