Ataxia

Ataxia means lack of coordination or unsteadiness. There are three major types:

(a) Friedreich’s Ataxia (FA)

FA is an inherited degenerative disorder that causes damage to the nervous system, resulting in symptoms ranging from muscle weakness and speech problems to heart disease. The ataxia results from neuronal degeneration in the spinal cord and peripheral nervous system. Symptoms usually begin between the ages of 5-15 years but may appear earlier or later. The first symptom is usually difficulty in walking. The ataxia usually worsens, spreading to the arms and trunk. Foot deformities such as clubfoot, flexion of the toes, hammer-toes or foot inversion may be early signs. Rapid, rhythmic, involuntary ocular movements are common. A late development maybe be scoliosis of the spine, and this could impair breathing. Heart disease is the most common cause of death in FA patients. The prevalence of FA in the UK is estimated to be 1 in every 50,000 people: perhaps 15 - 20 people in the Greater Glasgow Health Board area.

(b) Cerebellar Ataxias (CA)

There are numerous causes of cerebellar ataxia, including alcoholism, multiple sclerosis, brain tumours, and thyroid disease. If all these, and other diseases, can be excluded by means of neurological assessment and investigations, and if unsteadiness has come on relatively gradually or in early life, it is most likely that the unsteady person has ataxia caused by a genetic abnormality, even though there may not be anyone else in the family who is similarly affected. There are also late onset (i.e. in middle life or later) ataxias for which there is no obvious cause and in which genetic factors do not seem to be important.

Earlier onset cerebellar ataxia, or spastic ataxia, develops in childhood and looks very similar to Freidrich’s ataxia but tends to be less disabling. Stiffness of the legs is a common associated problem. The problems that develop in some people with Freidrich’s ataxia, such as heart disease and diabetes, do not occur. In most cases it seems likely that the problem is caused by a double dose of an abnormal gene, one dose coming from each parent, a mode of inheritance referred to as autosomal recessive. This pattern of inheritance applies to most ataxias which develop before the age of 20 years.

About two-thirds of people with ataxias developing in adult life (sometimes up until the age of 70 or more) do not have affected relatives, and we do not know the cause of these disorders. They are sometimes called "idiopathic" late onset ataxias (which basically means that no cause can be found). There are probably around 60 people with CA living in the Greater Glasgow Health Board area.

(c) Ataxia telangiectasia (A-T)

The first signs of A-T occur in early childhood: difficulty with control of he body posture and body movement (truncal ataxia).  The child may start to walk later than usual (afer 18 months), may be reluctant to let go of supporting people or objects, may continue to walk unsteadily for longer than normal, may be unable to stand still without tottering back and forth and may fall frequently.

Prominent blood vessels in the whites of the eyes usually occur by the age of 5 years.  These are the ocular telangiectasia of the condition and resemble those vessels seen in the eyes of much older people.   They can occasionally be present at birth yet in others may not develop until the teenage years.  Although potentially a cosmetic problem they do not bleed or itch.  It is their constant nature, not changing with time or weather or emotion, which marks them as different from other eye blood vessels.

Initially it may be hard to be sure that anything is amiss and some children seem to improve from three to five years, but eventually it becomes obvious that balance control is abnormal.  Walking becomes more strenuous and appears awkward, doors and walls are frequently used for support.  Running may, for a while, seem less affected;  this is because less balance is needed for quick movements than slower graceful ones.  At the beginning of the second decade of their lives most people with A-T start to use a wheelchair.  Towards the end of the first decade and the start of the second other problems come to light;  these can become as handicapping as the loss of body balance control.

The incidence of A-T in Caucasians is about 3 per million so the disorder is very rare, with probably fewer than 200 affected people in the UK.

Ataxia UK (West of Scotland branch)

Ataxia UK

Ataxia-Telangiectasia Society

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