What are the diagnostic criteria for MELAS?

MELAS Syndrome: Diagnostic Criteria, Symptoms & Evaluation

MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like Episodes) refers to an inherited mitochondrial disease. It is a matrilineal hereditary multisystem disease with a variety of clinical presentations. When a mutation occurs in mitochondrial DNA, MELAS syndrome is diagnosed.

The lack of resources in South Asian countries, including India, makes diagnosing MELAS syndrome difficult.

What is MELAS syndrome?

MELAS syndrome refers to a maternally inherited mitochondrial disorder, which is a rare condition. This MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) features symptoms such as myopathy(muscle weakness), stroke-like episodes, etc. It impacts the brain and muscles, resulting in neurological problems like seizures, dementia, and vision and hearing impairments, as well as other organ system involvement. 

Diagnostic Criteria for MELAS

MELAS syndrome affects the muscles and nervous system of a patient. It happens when mitochondria cells are unable to produce sufficient energy to function. Usually, people suffering from this syndrome are born with it, and their signs appear before turning 20 years of age.

The following are some symptoms of MELAS syndrome:

1. Dizziness or lack of balance
2. Slurred speech
3. Paralysis in one part of the body
4. Numbness or tingling sensation in one part of the body
5. Confusion
6. Double or blurred vision
7. Muscle cramps
8. Stomach ache
9. Extreme fatigue
10. Intellectual disability
11. Diabetes
12. Hearing issues
     

Melas syndrome can happen to anyone, but children only develop this syndrome through their mothers. Studies show that every 1 in 10,000 to 1 in 15,000 people struggles with this disease.

Severity of MELAS

Stroke-like episodes, which are a hallmark symptom in MELAS patients, often lead to neurological disorders. In addition, the abnormal functionality of mitochondria can damage the liver, kidney and heart. Talking to healthcare professionals might help manage the symptoms.

Diagnosis of MELAS

The diagnosis of MELAS depends on identifying the pathogenic variant in one of the genes through its clinical manifestations. The following are ways to diagnose MELAS:

1. Genetic Tests: Besides blood and urine tests of a patient, genetic tests like MT-TL1 gene testing and next-generation sequencing (NGS) are conducted.
2. MRIs: To visualise stroke-mimicking diseases that affect people before the age of 40, T2-weighted FLAIR imaging is used.
3. Tests of Cerebrospinal Fluid (CSF): These tests usually check the lactate levels in the blood to assess the cell counts and protein levels.
4. Muscle Biopsy (If needed): During initial gene testing, if a patient reports muscle weakness, a muscle biopsy could help medical professionals determine the intensity of MELAS.

Causes of MELAS Syndrome

MELAS syndrome is generally caused by mutations in mitochondrial DNA (mtDNA), which is a genetic disorder that is inherited from the mother. The general cause is a mutation in the MT-TL1 gene. These mutations impair the generation of necessary proteins, resulting in cellular energy deficits and impacting high-energy organs such as the brain and muscles. The vast majority of MELAS cases are caused by mtDNA mutations inherited from the mother. Rarely, a de novo (new) mutation in mtDNA can occur.
 

Treatment

Even though doctors still have not come up with a permanent solution to treat MELAS, they prescribe anti-seizure medications, amino acid-based medicines that help to reduce stroke-like episodes, insulin to treat diabetes, and certain types of childhood vaccines to manage the symptoms.

Since MELAS syndrome is not curable, patients have to live with it throughout their lives. Experts recommend that parents ensure their children do not miss out on childhood vaccinations. Furthermore, if the symptoms worsen, there are occupational therapists, physical therapists and social workers who can help.

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