Screening for mt-DNA mutations in optic neuritis of unknown cause

Objective To investigate mitochondrial DNA (mt-DNA) mutations in optic neur itis of unknown cause (ONUC) and to assess the practical value of mt-DNA mu tation detection in etiologically and differentially diagnosing ONUC. Methods Thirty patients with ONUC were screened for mt-DNA mutations of nt1 1778, nt3460 and nt15257 by using SSCP, mutation-specific primer PCR and se quencing. 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 mutat ions in ONUC patients is of great significance in diagnosing ONUC etiologic ally and significance differentially.