Information for patients, their families and helpers
The facts: The medical condition
- Small amounts of phytanic acid in the body are harmless but when the level rises in the blood it is a poison.
- Phytanic acid in the fat stores is less dangerous.
It is not known exactly how phytanic acid or related compounds poison the body, although the problems that occur in adult Refsum's disease are well recognized. The problems that occur in patients with adult Refsum's disease can be divided into 3 categories:
1. Bony abnormalities
These occur early in life, but only in a proportion of patients and they are rarely a major problem. The commonest congenital abnormalities are short fingers and toes but other bones and joints may be affected.
2. Slowly progressive problems
a. Retinitis pigmentosa
The most important and serious abnormality in adult Refsum's disease is retinitis pigmentosa, a degeneration of the retina, which usually begins mildly in childhood and then slowly progresses. The main symptoms of retinitis pigmentosa are poor vision in the dark and contraction of the visual fields, which means that only objects in the centre of vision are easily seen. It has not been possible to show a relationship between the severity of the retinitis and the level of phytanic acid in the blood although there is some evidence that, if the level of phytanic acid in the body can be kept low, the blindness will not get worse. Unfortunately the retina of the eye is a very sensitive structure and when damaged does not have powers of recovery. Hence, if one is to prevent blindness in adult Refsum's disease, it will be necessary to treat the illness early and prevent retinal damage, rather than to treat it when it is severe. Other eye pathology can occur in adult Refsum's disease.
b. Poor sense of smell
All patients with adult Refsum's disease have a poor sense of smell from a young age. In order to detect this the sensation of smell must be tested appropriately by a suitable medical technique. It is not sufficient to ask a patient if he/she can smell normally as these patients may not know what normal smell is and be unaware that their ability to smell is well below the normal.
Some patients develop deafness.
3. Problems which can change rapidly
The weakness and unsteadiness of gait which patients with adult Refsum's disease get can come on quickly, and if treated can improve quickly. The unsteadiness is due to damage to the nerves. Only if it has been present and untreated for a long time will it fail to improve with treatment. It is this symptom which may immobilize a patient, especially if vision is severely affected. There are also other less common problems in this group including a dry rash, ichthyosis. The heart muscle can be damaged in severe adult Refsum's disease, but this is rare in patients whose phytanic acid is controlled by appropriate management. There are other rarer complications in this category.
Next: Who is at risk?
Page last updated 26 June 2006