Gaucher disease is part of a rare group of genetic metabolic diseases which are caused by an inherited deficiency of the enzyme glucocerebrosidase. The most common form, Type 1 affects 1 in 40,000 to 60,000 individuals in the general population. In Type 1 symptoms may appear at any time from infancy to old age. The disease is associated with anaemia (a decrease in the amount of red blood cells), fatigue (tiredness), bruising and an increased tendency to bleed. An enlarged spleen and liver with stomach swelling may also occur as well as bone pain, fractures and bone deterioration. Type 1 was formerly considered not to affect the brain or nervous system. Some patients with Type 1 Gaucher disease have no symptoms, while others develop serious symptoms that can be life threatening; latterly Parkinsonism and Dementia with Lewy bodies has been noted to occur with increased frequency in patients with this variant of Gaucher disease compared with healthy control subjects in an age-matched population.