Objective: To investigate mitochondrial DNA (mt-DNA) mutations in optic neuritis of unknown cause (ONUC) and to assess the practical value of mt-DNA mutation detection in etiologically and differentially diagnosing ONUC.
Methods: Thirty patients with ONUC were screened for mt-DNA mutations of nt11778, nt3460 and nt15257 by using SSCP, mutation-specific primer PCR and sequencing.
Results: mt-DNA mutations were found in twelve of thirty ONUC patients. All of the mutations were at nt11778 position, but no one at nt3460 and nt15257.
Conclusions: Forty percent (12/30) of ONUC patients were caused by an mt-DNA mutation. Combined with other routine measures, screening for mt-DNA mutations in ONUC patients is of great significance in diagnosing ONUC etiologically and differentially.