Screening of PEO1 and mitochondrial genes in sporadic cases of ophthalmoplegia

Aim: To screen the gene PEO1 and mitochondrial genes in sporadic cases of rare progressive external ophthalmoplegia (PEO) patients from North India. Materials and Methods: The nuclear and mitochondrial DNA was isolated from the sporadic PEO patients, and bi-directional sequencing was done in gene PEO1 and mitochondrial genes to capture the mutations relevant to the PEO disease. Results: In the present study, none of the mutations were reported in the coding region of PEO1 gene, while four mutations were observed in mtDNA genes, namely NADH dehydrogenase subunit 2 (ND2), tRNA-Trp, non-coding nucleotides (MT-NC3), and NADH dehydrogenase subunit 5 (MT-ND5). Our study revealed two novel mutations, one in tRNA-Trp and the other in ND2 gene, which may have role in sporadic cases of PEO patients. The absence of novel conserved mutation in tRNA-Trp gene was also confirmed in 110 ethnically matched controls. Conclusion: The sporadic case of PEO disease is not associated with mutations in nuclear gene PEO1 . The novel mutation in tRNA-Trp gene and ND2 mutations may have role in the disease.