MERRF-like phenotype associated with a rare mitochondrial trnaile mutation (m.4284 G>A)

Area of Science:

• Genetics
• Neurology
• Mitochondrial Diseases

Background:

• Myoclonic epilepsy with ragged-red fibres (MERRF) is a rare mitochondrial disorder.
• MERRF is typically associated with mutations in the mitochondrial transfer RNA Lys gene (MT-TK).

Observation:

• An 8-year-old girl presented with clinical features consistent with MERRF.
• Common MERRF-associated mutations were excluded through genetic testing.

Findings:

• Whole mitochondrial genome sequencing identified a novel m.4284 G>A mutation in the mitochondrial transfer RNA Ile gene (MT-TI).
• This MT-TI mutation has been previously reported in a family with variable symptoms but not definitively linked to MERRF.

Implications:

• This case broadens the spectrum of mutations associated with the MERRF phenotype.
• Comprehensive genetic analysis is crucial for diagnosing mitochondrial diseases when common mutations are absent.