Mitochondrial Disorder

Mitochondrial disorders are genetic conditions caused by mutations in mitochondrial DNA (mtDNA). Unlike nuclear DNA, mitochondrial DNA is exclusively inherited from the mother, as mitochondria in the zygote come only from the egg cell (ovum) during fertilisation.

Causes:

• Mutations in mitochondrial DNA lead to defective mitochondria, which disrupt the production of energy in cells.
• Mitochondrial disorders are passed down only through the mother (maternally inherited).

Example of a Mitochondrial Disorder: Leber Hereditary Optic Neuropathy (LHON)

LHON is a mitochondrial disorder that causes vision loss due to damage to the optic nerve. The mutation in mitochondrial DNA disrupts energy production in the optic nerve cells, leading to their degeneration.

Symptoms:

• Sudden or gradual vision loss, typically in young adults.
• Central vision is primarily affected, which impacts daily activities like reading or recognising faces.

Since mitochondria are the powerhouse of the cell, the most energy-demanding organs are affected, including the brain, eyes, heart, and muscles.

Diagnosis:

• Genetic testing is used to identify mutations in mitochondrial DNA.
• Specialised tests, such as muscle biopsies, may be conducted to assess mitochondrial function.

Treatment:

• Currently, there is no cure for mitochondrial disorders.
• Symptomatic treatments, such as physical therapy, nutritional supplements, and energy-supportive diets, can help manage the condition.
• Reducing stress, avoiding toxins, and maintaining a balanced diet can help minimise symptoms.