Overview

Types

Some types of ataxia affect children from an early age, while other types may not develop until much later in adulthood.

Depending on the type of ataxia, the symptoms may stay the same, get progressively worse, or slowly improve.

Some of the main types of ataxia are described below.

Friedreich's ataxia

Friedreich's ataxia is the most common type of hereditary ataxia (caused by genes you've inherited). It's thought to affect at least 1 in every 50,000 people.

Symptoms usually first develop before the age of 25, although it can develop in people much older than this.

Signs and symptoms of Friedreich's ataxia can include:

• problems with balance and co-ordination, often causing wobbliness, clumsiness and frequent falls
• increasingly slurred, slow and unclear speech (dysarthria)
• increasing weakness in the legs – many people find walking difficult and need to use a wheelchair after around 10 to 20 years
• difficulty swallowing (dysphagia)
• abnormal curvature of the spine (scoliosis)
• total or partial vision loss and hearing loss
• diabetes
• thickening of the heart muscles (hypertrophic cardiomyopathy), which can cause chest pain, breathlessness and an irregular heartbeat
• loss of sensation in the hands and feet (peripheral neuropathy)

The symptoms of Friedreich's ataxia usually get gradually worse over many years. People with the condition tend to have a shorter life expectancy than normal. Many people live until at least their 30s, and some can live into their 60s or beyond.

Ataxia-telangiectasia

Ataxia-telangiectasia (AT) is a rarer type of hereditary ataxia. Symptoms usually begin in early childhood, although they can sometimes develop later.

Signs and symptoms of AT can include:

• difficulty walking – most children need to use a wheelchair by 10 years of age
• increasingly slurred, slow and unclear speech (dysarthria)
• difficulty swallowing (dysphagia)
• small spider-like clusters of red blood vessels in the corner of their eyes and on their cheeks (telangiectasias)
• very slow eye movements, which may mean the person has to move their head a lot to compensate for this
• a weakened immune system – children with AT are more vulnerable to infections, particularly infections of the sinuses, lungs and airways, such as pneumonia
• an increased risk of cancer, particularly acute lymphoblastic leukaemia or lymphoma

The symptoms of AT tend to get worse quite quickly. People with the condition usually live until the age of 19 to 25, although some may live into their 50s.

Spinocerebellar ataxias

Spinocerebellar ataxias (SCAs) are a group of hereditary ataxias that often don't begin until adulthood, affecting people from the age of 25 up to 80, depending on the type of SCA. Occasionally, some types of SCA begin in childhood.

The symptoms vary depending on the type of SCA. They can include:

• problems with balance and co-ordination – many people find walking difficult and need to use a wheelchair after a few years
• increasingly slurred, slow and unclear speech (dysarthria)
• difficulty swallowing (dysphagia)
• muscle stiffness and cramps
• loss of sensation in the hands and feet (peripheral neuropathy)
• memory loss and difficulties with spoken language
• slow eye movement, which means people have to move their head to compensate
• reduced bladder control (urinary urgency or incontinence)

Episodic ataxia

Episodic ataxia is a rare and unusual type of hereditary ataxia where someone experiences episodes of ataxia, but the rest of the time they have no or only mild symptoms.

During an episode, someone with episodic ataxia may experience:

• problems with balance and co-ordination
• slurred, slow and unclear speech (dysarthria)
• muscle spasms
• involuntary eye movements (nystagmus)
• vertigo, migraines and tinnitus

Episodic ataxia usually first develops during the teenage years. The episodes can last from several minutes to hours and are usually the result of certain triggers, such as sudden movement, stress, exercise, caffeine or alcohol.

The symptoms of episodic ataxia may disappear as a person gets older, although sometimes the condition gets gradually worse over time. Medication can often help control attacks, and life expectancy is usually normal.

Other types of ataxia

There are also a number of other types of ataxia that tend to have similar symptoms to those mentioned above. These include:

• acquired ataxia – this can affect people of any age and usually develops very quickly over the course of a few days, or sometimes hours; it may improve over time, stay the same or get slowly worse
• idiopathic late-onset cerebellar ataxia (ILOCA) – this usually begins at around 50 years of age and gets slowly worse over time
• ataxia with vitamin E deficiency – a similar condition to Friedreich's ataxia caused by problems with the body's ability to use vitamin E in the diet; it's often possible to control the symptoms with vitamin E supplements

Who can get it

Ataxia is usually caused by damage to a part of the brain known as the cerebellum, but it can also be caused by damage to the spinal cord or other nerves.

The spinal cord is a long bundle of nerves that runs down the spine and connects the brain to all other parts of the body.

The cerebellum is located at the base of the brain and is responsible for controlling:

• walking and sitting balance
• limb co-ordination
• eye movements
• speech

Damage can occur as a result of injury or illness (acquired ataxia) or because the cerebellum or spinal cord degenerates because of an inherited faulty gene (hereditary ataxia).

Sometimes there is no clear reason why the cerebellum and spinal cord become damaged. This is the case for people with idiopathic late-onset cerebellar ataxia (ILOA).

Acquired ataxia

Acquired ataxia can have a wide range of potential causes, including:

• severe head injury - after a car crash or a fall, for example
• bacterial brain infection, such as meningitis or encephalitis (an infection of the brain itself)
• viral infection – some viral infections, such as chickenpox or measles can spread to the brain, although this is very rare
• conditions that disrupt the supply of blood to the brain, such as a stroke, haemorrhage or a transient ischaemic attack
• cerebral palsy – a condition that can occur  if the brain develops abnormally or is damaged before, during or shortly after birth
• multiple sclerosis – a long-term condition that damages the nerve fibres of the central nervous system
• sustained long-term alcohol misuse
• an underactive thyroid gland
• vitamin B12 deficiency
• brain tumours and other types of cancer
• certain toxic chemicals, such as mercury and some solvents - these can trigger ataxia if a person is exposed to enough of them
• medications such as benzodiazepines can occasionally trigger ataxia as a side effect

Hereditary ataxia

Hereditary ataxia is caused by a faulty gene. Genes are units of DNA that determine a particular characteristic, such as sex or eye colour. A baby receives 2 copies of every gene – one from their mother and one from their father.

There are 2 ways that ataxia can be inherited:

• autosomal recessive – Friedreich's ataxia and ataxia-telangiectasia are inherited in this way
• autosomal dominant – episodic ataxia and some cases of spinocerebellar ataxia are inherited in this way

These are described in more detail in the following sections.

Autosomal recessive

When ataxia is autosomal recessive, it means the affected person has inherited the mutated gene from both their mother and their father.

If they only received one mutated gene from either parent, the other normal gene will cancel out the effects of the faulty gene and they will be a carrier of the condition. This means they don't have the condition themselves, but could pass it on to their children if their partner is also a carrier of the faulty gene.

It's estimated around 1 in every 85 people are carriers of the mutated gene that causes Friedreich's ataxia. Fewer people than this are carriers of the mutated gene that causes ataxia-telangiectasia.

If 2 carriers of the mutated gene were to have a baby, there would be a:

• 1 in 4 chance the baby would receive a pair of normal genes
• 2 in 3 chance the baby would receive 1normal gene and 1 mutated gene (be a carrier)
• 1 in 4 chance the baby would receive a pair of mutated genes and develop ataxia

If you have autosomal recessive ataxia and your partner is a carrier, there is a 1 in 2 chance your baby will receive 1 normal gene and 1 mutated gene and will be a carrier, and a 1 in 2 chance your baby will receive a pair of mutated genes and develop ataxia.

If you have autosomal recessive ataxia and your partner doesn't and they aren't a carrier, there's no risk of any of your children developing ataxia. This is because your mutated gene will be cancelled out by your partner's normal gene. Your children will be carriers, however.

Autosomal dominant

When ataxia is autosomal dominant, you can develop the condition if you receive a single faulty gene, either from your mother or father. This is because the mutation is strong enough to override the other normal gene.

If you have autosomal dominant ataxia, any children you have will have a 1 in 2 chance of developing ataxia.

Diagnosis

Visit your GP if you or your child have unexplained symptoms such as balance and co-ordination problems or difficulty walking, talking or swallowing.

Family and medical history

Your GP may ask whether you have any family history of ataxia. They will also want to know about the progression of your symptoms. They might carry out a simple assessment of your balance, walking and co-ordination.

Your GP may also ask how much alcohol you drink and whether you're taking any form of medication. This is because excessive drinking and certain medications can cause ataxia-like symptoms in some people.

You may be referred for a series of tests to rule out other possible causes of your symptoms, such as an infection. The tests will probably include blood and urine tests.

Further testing

If your symptoms suggest you may have acquired ataxia because of a serious underlying condition, it's likely you'll be admitted immediately to your nearest hospital.

Otherwise, you'll be referred to a neurologist (a specialist in brain and nervous system conditions) for further testing or, in the case of children, a paediatrician. Some of the tests you may have are described below.

Genetic testing

Genetic testing involves taking a sample of blood and testing the DNA in it for any genetic mutation known to cause ataxia.

Currently, tests can detect the mutations responsible for Friedreich's ataxia, ataxia-telangiectasia and most of the spinocerebellar ataxias.

Brain scans

Brain scans can be used to check for physical abnormalities in the brain that could be caused by certain types of hereditary ataxia. They can also be used to check for other problems that may affect your brain, such as a brain tumour.

The 2 most widely used brain imaging scans are:

• magnetic resonance imaging (MRI) scan – this uses a strong magnetic field and radio waves to produce detailed scans of the soft tissue of the brain
• computerised tomography (CT) scan – where a series of X-rays are taken and assembled by a computer into a detailed three-dimensional image of your brain

Other tests

Some of the other tests you may have to help diagnose ataxia and determine how severe it is can include:

• a lumbar puncture – where a sample of cerebrospinal fluid is taken from the base of the spine to check it for infection and any other abnormalities
• nerve conduction studies and electromyography (EMG) – tests used to assess the electrical activity in nerves and muscles
• videofluoroscopy – a continuous moving X-ray taken while you swallow different types of food and drink
• an electrocardiogram (ECG) –  an assessment of the electrical activity of the heart
• an echocardiogram – an ultrasound scan of the heart

Treatment