An improved high-throughput dried blood spot screening method for Gaucher disease.

Gaucher disease is a lysosomal storage disorder caused by the deficiency of the lysosomal hydrolase glucocerebrosidase (β-glucocerebrosidase or acid β-D-glucosidase, GBA, EC 3.2.1.45). The deficiency of GBA leads to the accumulation of glucosylceramide (glucocerebroside) in the lysosomes of cells in the monocyte/ macrophage system. In Gaucher disease, glycosphingolipid-engorged cells displace normal cells in the liver, spleen and bonemarrow, which can lead to hepatosplenomegaly, thrombocytopenia, organ dysfunction, and skeletal deterioration [1]. The diagnosis of Gaucher disease is confirmed by measuring GBA activity in peripheral blood leukocytes; however, many patients are misdiagnosed or remain undiagnosed because Gaucher disease is rare and patients can have heterogeneous clinical symptoms [2]. The use of a simple screening method in high risk populations could increase the diagnostic rate of Gaucher disease and permit therapeutic intervention as needed to prevent serious complications. A high-throughput and reliable fluorescent assay was developed using the β-D-glucosidase substrate 4-MUG and CBE, an irreversible inhibitor of GBA that allows the distinction between GBA and other β-glucosidase isoenzymes [3]. Specimens from 20 previously diagnosed Gaucher disease patients were collected with written informed consent. Specimens from 193