IllnessMELAS - mt enzephalomyopathy, lactacidosis, stroke

NGS +

[Sanger]

MELAS affects various body functions and systems, especially the brain and nervous system as well as the muscles. Symptoms often appear in childhood after initially normal development, although signs can begin at any age. Early symptoms may include muscle weakness and pain, recurrent headaches and seizures. Most affected individuals experience stroke-like episodes before age 40. These episodes are often accompanied by hemiparesis, altered consciousness, visual disturbances, seizures and migraine-like headaches. Repeated stroke-like episodes can progressively damage the brain, leading to vision loss, movement disorders and dementia. Most MELAS patients present with lactacidosis, rarely myoclonus, ataxia, hearing loss, cardiac and renal problems, diabetes, as well as hormonal imbalances. A single mutation in the transfer RNA gene MT-TL1 causes more than 80% of MELAS cases. In addition to another 30 mitochondrial mutations, this genetically heterogeneous disease can arise from de novo mutations of nuclear genes (with classical transfer patterns). The diagnostic yield in individuals with suspected nuclear gene-related mitochondrial disorders is generally only up to 50%. Therefore, a negative DNA test result does not exclude the clinical diagnosis.

Reference: https://www.ncbi.nlm.nih.gov/books/NBK1233/

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