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Don’t fight Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes alone.
Find your community on the free RareGuru App.Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) affects many parts of the body, particularly the brain and nervous system (encephalo-) and muscles (myopathy). Symptoms typically begin in childhood and may include muscle weakness and pain, recurrent headaches, loss of appetite, vomiting, and seizures. Most affected individuals experience stroke-like episodes beginning before age 40. People with MELAS can also have a buildup of lactic acid in their bodies that can lead to vomiting, abdominal pain, fatigue, muscle weakness, and difficulty breathing. The genes associated with MELAS are located in mitochondrial DNA and therefore follow a maternal inheritance pattern (also called mitochondrial inheritance). MELAS can be inherited from the mother only, because only females pass mitochondrial DNA to their children. In some cases, MELAS results from a new mutation that was not inherited from a person's mother.
Source: GARD Last updated on 05-01-20
The signs and symptoms of MELAS often appear in childhood following a period of normal development. Early symptoms may include muscle weakness and pain, recurrent headaches, loss of appetite, vomiting, and seizures. Most affected individuals experience stroke-like episodes beginning before age 40. These episodes may involve temporary muscle weakness on one side of the body, altered consciousness, vision abnormalities, seizures, and severe headaches resembling migraines. Repeated stroke-like episodes can progressively damage the brain, leading to vision loss, problems with movement, and a loss of intellectual function.
Many people with MELAS have a buildup of lactic acid in their bodies (lactic acidosis). This can lead to vomiting, abdominal pain, extreme fatigue, muscle weakness, and difficulty breathing. Involuntary muscle spasms, impaired muscle coordination, hearing loss, heart and kidney problems, diabetes, and hormonal imbalances may also occur.
Last updated on 05-01-20
MELAS is caused by mutations in mitochondrial DNA (mtDNA) and is therefore transmitted by maternal inheritance (also called mitochondrial inheritance). This type of inheritance applies to all conditions caused by genes in mtDNA. Mitochondria are structures in each cell that turn molecules into energy, and each contain a small amount of DNA. Only egg cells (not sperm cells) contribute mitochondria to offspring, so only females can pass on mitochondrial mutations to their children. Conditions resulting from mutations in mtDNA can appear in every generation of a family and can affect both males and females. In most cases, people with MELAS inherit an altered mitochondrial gene from their mother. Less commonly, the condition results from a new mutation in a mitochondrial gene and occurs in an individual with no history of MELAS in the family.
Last updated on 05-01-20
As mentioned above, muscle weakness and extreme fatigue are common in this condition.
Last updated on 05-01-20
The risk to the siblings of an individual affected with MELAS depends on the genetic status of their mother. If their mother has the mtDNA mutation, all of the siblings of the affected individual will inherit the disease-causing mtDNA mutation; however, the siblings may or may not have symptoms. One study reported that women with higher levels of the mutated mtDNA in their blood have a greater likelihood of having affected offspring (i.e. children with symptoms of the condition).
Unfortunately, it is not possible to predict whether an individual with an mtDNA mutation will have specific symptoms. The possible effects of an mtDNA mutation depend on a combination of factors, including the severity of the mutation, the percentage of mitochondria that have the mutation, and the organs and tissues in which the mutated mitochondria are located. Different family members often inherit different percentages of mutated mtDNA and therefore can have a wide range of clinical symptoms. Test results of at-risk family members who don't currently have symptoms are very hard to interpret.
Individuals concerned about specific risks to themselves or family members should speak with a genetics professional.
Last updated on 05-01-20
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