Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is a rare maternally inherited mitochondrial disorder that predominantly affects the nervous system and muscles. MELAS typically appears in childhood after a period of normal early development. This condition manifests with recurrent episodes of encephalopathy, myopathy, headache, and focal neurological deficits in children or young adults, usually between the ages of 2 and 15. A distinctive feature of the syndrome is the occurrence of stroke-like episodes leading to hemiparesis, hemianopia, or cortical blindness. Other notable manifestations include focal or generalized seizures, recurring migraine-like headaches, vomiting, short stature, hearing loss, and muscle weakness. Instances of infantile cases and cases where the symptoms appear after a delay of 15 and 40 have been documented.

A nucleotide substitution in transfer RNA (tRNA) is responsible for most cases of the disease. One specific substitution, the m.3243A>G (A-to-G substitution at nucleotide 3243), is responsible for 80% of cases, whereas another tRNA variation, the m.3271T>C (T-to-C substitution at nucleotide 3271), accounts for the remaining cases. MELAS is characterized by progressive deterioration of the nervous system that leads to neurological impairment and dementia in adolescence or early adulthood.

The clinical diagnosis of this condition is based on several factors, including clinical symptoms, genetic variation analysis, imaging findings, and, in some cases, muscle biopsy. During acute attacks, characteristic biochemical changes in the serum can be observed, and distinctive magnetic resonance imaging (MRI) findings reveal cortical infarcts with restricted diffusion unrelated to any specific vascular territory. Confirming the diagnosis usually requires mitochondrial genetic testing.

Unfortunately, there is currently no known treatment that can slow or halt the progression of the disease. The primary emphasis of treatment focuses on symptom management through a multidisciplinary team approach. Therapeutic agents commonly used include L-arginine, carnitine, and coenzyme Q10, selected for their potential impact on mitochondrial function.

Disclosure:Shermila Pia declares no relevant financial relationships with ineligible companies.

Disclosure:Forshing Lui declares no relevant financial relationships with ineligible companies.