MT-CO1 – MELAS syndrome

Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is most commonly associated with an A3243G transition in the tRNA^Leu(UUR) gene. Multiple case reports included MT-CO1 in mtDNA sequencing panels but did not identify any pathogenic MT-CO1 variants in MELAS patients (PMID:9243242, PMID:9884447). A cohort study of 91 patients with non-classic mitochondrial encephalomyopathies found 21 with the 3243A>G mutation but no MT-CO1 alterations (PMID:8392410). No segregation of MT-CO1 variants with MELAS has been reported, and no probands carry missense, truncating, splice or structural changes in MT-CO1. There are no functional studies in patient cells or model organisms that link MT-CO1 perturbation to the MELAS phenotype. Consequently, current evidence is insufficient to support a causative role for MT-CO1 in MELAS. Key Take-home: MT-CO1 has limited clinical utility in MELAS diagnostic workflows due to the absence of reported disease-causing variants.

References

• European journal of pediatrics • 1997 • Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) triggered by valproate therapy. PMID:9243242
• Zhonghua yi xue za zhi = Chinese medical journal; Free China ed • 1998 • Childhood MELAS syndrome presenting with seizure and cortical blindness: a case report. PMID:9884447
• Neuromuscular disorders : NMD • 1993 • Atypical clinical presentations associated with the MELAS mutation at position 3243 of human mitochondrial DNA. PMID:8392410

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