Headache and mitochondrial disorders

Area of Science:

• Neurology
• Genetics
• Biochemistry

Background:

• Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke (MELAS) is a rare genetic disorder.
• Patients present with a constellation of symptoms including neurological deficits and muscle abnormalities.
• Distinguishing MELAS from similar mitochondrial disorders is crucial for accurate diagnosis and management.

Purpose of the Study:

• To describe the clinical features of patients with MELAS.
• To differentiate MELAS from Kearns-Sayre syndrome and myoclonus epilepsy ragged red fiber syndrome.
• To highlight the potential maternal inheritance pattern of MELAS.

Main Methods:

• Clinical case reporting of 2 patients with MELAS.
• Review of previously reported cases (9 patients).
• Analysis of clinical features including muscle biopsy findings (ragged red fibers), developmental history, stature, and neurological manifestations.

Main Results:

• Patients with MELAS exhibit ragged red fibers on muscle biopsy, normal early development, short stature, seizures, and neurological deficits (hemiparesis, hemianopia, cortical blindness).
• Lactic acidemia is a common biochemical finding in MELAS.
• MELAS can be distinguished from Kearns-Sayre syndrome and myoclonus epilepsy ragged red fiber syndrome based on distinct clinical presentations.

Conclusions:

• MELAS represents a distinct clinical syndrome with characteristic features.
• Maternal inheritance is suggested for MELAS.
• While ragged red fibers indicate electron transport system abnormalities, the specific biochemical defects in MELAS and related syndromes require further elucidation.