The pathogenic m.3243A>T mitochondrial DNA mutation is associated with a variable neurological phenotype

Area of Science:

• Genetics
• Mitochondrial Biology
• Neurology

Background:

• The m.3243A>G mutation in the mitochondrial tRNA(Leu(UUR)) (MTTL1) gene is a known cause of mitochondrial DNA disease.
• The m.3243A>T transversion at the same site is less common but has been linked to encephalopathy and lactic acidosis.

Observation:

• This study reports on two additional patients with the m.3243A>T mutation.
• One patient presented with chronic progressive external ophthalmoplegia (CPEO).
• The other patient exhibited sensorineural hearing loss.

Findings:

• Single fiber mutation studies confirmed the segregation of the m.3243A>T mutation.
• The mutation was associated with cytochrome c oxidase (COX) deficiency.

Implications:

• These findings expand the known clinical spectrum associated with the m.3243A>T mitochondrial DNA mutation.
• This highlights the importance of genetic investigation for diverse neurological and ophthalmological presentations.
• Further research may clarify the pathogenic mechanisms and therapeutic strategies for m.3243A>T-related disorders.