Clinical Presentation
What neurological feature is considered a hallmark of MELAS, and what makes it unique?
Stroke-like episodes without vascular occlusion
What is the inheritance pattern of MELAS?
Maternally inherited mitochondrial disorder
What kind of DNA analysis is used in genetic evaluation?
Mitochondrial DNA analysis
When does symptom onset of MELAS typically occur?
In childhood, usually between ages 2 and 15
What is the estimated prevalence rate of MELAS in the adult population?
1/700
What are the relevant laboratory tests for MELAS?
Serum lactic acid, serum pyruvic acid, cerebrospinal fluid (CSF) lactic acid, and CSF pyruvic acid.
Characteristic symptoms of MELAS include seizures, recurrent migraine-like headaches, vomiting, short stature, hearing loss, and what endocrine disorder?
Diabetes mellitus
What does heteroplasmy mean in MELAS?
Having both mutant and “normal” mitochondrial DNA in a cell
What imaging studies may be performed in the evaluation of MELAS?
Computed tomography (CT), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and positron emission tomography (PET)
What is the most common mutation in MELAS?
Adenine to guanine substitution in the MT-TL1 gene