In Friedreich ataxia, the nervous system is affected and movement, balance, speech, and sensations are affected. In addition to the heart, eyes, ears, and spine, Friedreich ataxia can affect the heart, eyes, ears, and spine as well. Friedreich ataxia usually develops in childhood or adolescence, although it may manifest later in life as well. The symptoms and complications can be managed with treatments.
An individual with Friedreich ataxia has a mutation in the gene FXN, which normally produces a protein called frataxin. In order for mitochondria, the energy-producing parts of the cells, to function properly, frataxin must be present. In the absence of frataxin, mitochondria become damaged and produce harmful substances, which can damage the nerves and other tissues.
Both parents must have a copy of the mutated gene and pass it on to their child in order for Friedreich ataxia to be inherited autosomally recessively. The chances of a child with Friedreich ataxia are 25% if both parents work. If only one parent has the mutation, the child will be a carrier but will not have the disease.
According to the severity and progression of Friedreich ataxia, symptoms vary from person to person. A common symptom is difficulty walking, caused by damage to the spinal cord and cerebellum, the part of the brain responsible for balance and coordination. Other symptoms may include:
Loss of sensation in the arms and legs, especially in the feet and hands
Muscle weakness and wasting
Slurred speech and difficulty swallowing
Hearing loss and vision problems
Involuntary eye movements
Foot deformities, such as high arches or curled toes
Scoliosis, or curvature of the spine
Heart problems, such as irregular heartbeat, chest pain, or heart failure
Diabetes, or high blood sugar levels
The symptoms of Friedreich ataxia usually worsen over time and can affect the quality of life and life expectancy of the affected individuals.
As part of the medical history, physical examination, and genetic testing, Friedreich ataxia is diagnosed. A physical examination may examine reflexes, sensation, muscle strength, coordination, and eye movements. As well as confirming the presence of the FXN mutation, genetic testing can also be used for prenatal diagnosis and carrier testing.
Other tests may be done to assess the function of the heart, eyes, ears, and nerves. These may include:
Electrocardiogram (ECG), which measures the electrical activity of the heart
Echocardiogram, which uses sound waves to create an image of the heart
Audiometry, which tests the hearing ability
Visual evoked potentials (VEP), which measure the response of the brain to visual stimuli
Nerve conduction studies (NCS) and electromyography (EMG), which measure the electrical activity of the nerves and muscles
There is no specific treatment for Friedreich ataxia, but there are therapies that can help manage the symptoms and prevent or delay the complications. These may include:
Medications, such as antioxidants, anti-inflammatory drugs, or drugs that improve the heart function or lower the blood sugar levels
Physical therapy, which can help maintain muscle strength, flexibility, and mobility
Occupational therapy, which can help with daily activities and adaptive devices
Speech therapy, which can help with communication and swallowing
Orthopedic surgery, which can correct foot deformities or scoliosis
Cardiac surgery, which can treat severe heart problems
Cochlear implants, which can restore hearing in some cases
In addition, regular check-ups and monitoring are important to detect and treat any changes in the condition.
Those who have a family history of Friedreich ataxia or who carry the mutation can benefit from genetic counseling. It is possible for genetic counselors to provide families with information about the risk of having a child with Friedreich ataxia, the options for prenatal or preimplantation genetic diagnosis, and the support and resources available to them.
