Tight linkage between type III Gaucher's disease (Norrbottnian type) and a MspI polymorphism within the gene for human glucocerebrosidase.

A MspI polymorphism was detected in the beta-glucocerebrosidase gene in 10 Swedish families affected by type III Gaucher's disease. The sizes of the polymorphic fragments were 1.70 and 1.75 kb and the disease was found to segregate with the 1.70-kb fragment in 32 meioses. Only the 1.75-kb fragment was detected in families with no history of Gaucher's disease. The results indicate that the mutation causing type III Gaucher's disease has occurred once within the Swedish population. The polymorphism is useful for carrier detection since biochemical tests sometimes give inconclusive results.