Abstract
Purpose :
Leber hereditary optic neuropathy (LHON) is a common cause of acute vision loss in young adults and is caused by mtDNA primary mutations. Routine clinical evaluation of mtDNA primary mutations has been performed in our lab since 1995. In this study, we systemically reviewed our results and further analyzed the entire coding sequencing of the MT-ND4, MT-ND6, and MT-ND1.
Methods :
Totally 3013 probands suspected with LHON were referred to our lab between 1995 and 2015. Mitochondrial DNA (mtDNA) was prepared from peripheral venous blood. The four primary mutations (G11778A, T14484C, G3460A, and G3635A) were initially detected by using allele-specific amplification or/and Sanger sequencing. Subsequently, the entire coding and adjacent sequences of the MT-ND4, MT-ND6, and MT-ND1 genes were further analyzed by Sanger sequencing for 1012 probands without any one of the four primary mutations.
Results :
The four primary mutations (G11779A, T14484C, G3460A, and G3635A) were detected in 989, 124, 19, and 13 of the 3013 probands suspected with LHON, respectively. Each of the five uncommon primary mutations was found in one case, respectively, including G3700A, G3733A, G4171A, G14459A, and A14495G. In addition, seven novel putative potential LHON-causative mutations were detected in 8 of the 1012 probands. Overall, 38.43% (1158/3013) patients suspected with LHON had one of these mutations. Heteroplasmy of mutations is uncommon in our series. Re-evaluation of part of these samples by another lab revealed misdiagnosis in one case.
Conclusions :
These study provide an overview of the mutation spectrum and associated frequencies o the MT-ND4, MT-ND6, AND MT-ND1 genes in Southern Chinese. New mutations in these three genes are very rare in probands without one of the four common primary mutations. Additional analysis of other candidate genes and further clinical clarification for those probands without those mtDNA pathogenic mutations may enrich our understanding of optic neuropathy.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.