2.1 Gaucher disease is an inherited lysosomal storage disorder. It is caused by deficiency of the enzyme glucocerebrosidase. This deficiency leads to the inappropriate storage of complex lipids in some types of cell. This creates Gaucher cells, which occur throughout the liver, spleen, bone marrow and occasionally the lungs. There are 3 subtypes of Gaucher disease, of which type 1 (non-neuronopathic) is the most prevalent. All types of Gaucher disease are associated with a variety of symptoms, including pain, fatigue, anaemia, thrombocytopenia, jaundice, bone damage, and liver and spleen enlargement.
2.2 There are limited data available on the epidemiology of Gaucher disease. The overall frequency of all types of Gaucher disease is about 1 in 50,000 to 1 in 100,000 live births. Over 90% of people affected have type 1 Gaucher disease. The prevalence of type 1 Gaucher disease is estimated to be 1 in 200,000 in non-Ashkenazi Europeans, which equates to about 250 people in England and Wales. It is more common in people of Ashkenazi family origin, with a frequency of about 1 in 500 to 1 in 1,000 live births. Clinical experts estimate that there are 350 to 400 patients with Gaucher disease (types 1, 2 and 3) in England, and 50 to 100 patients could be eligible for treatment with eliglustat.
2.3 The company submission states that the natural history of untreated disease before the availability of enzyme replacement therapy is poorly documented, and there is limited information on life expectancy for people with Gaucher disease. People who present below the median age of onset of about 14 years with massive splenomegaly and hypersplenism have a particularly poor prognosis. These patients usually develop bone disease and immobility in the third or fourth decade of life, with a high early mortality.