Cliriicul Genetics zyxwvutsrq 1978: zyxwvuts 13: 145-153 zyxwvut Synthetic substrate 13-glucosidase activity in leukocytes: A reproducible method for the identification of patients and carriers of Gaucher‘s disease DAVID A. WENGER, CAMERON CLARK”, MARTHA SATTLER AND CANDACE WHARTON Department of Pediatrics, University of Colorado Medical Center, Denver, Colorado, U.S.A. A method is described for the identification of patients and carriers of Gaucher’s dis- case, using leukocytes from a small volume of blood. The fluorogenic substrate, 4-methyl- zy umbelliferyl-P-D-glucopyranoside, was assayed in the presence of pure sodium tauro- cholate (2.5 mg/ml) and Triton X-100 (2.0 mg/ml). Some commercial brands of pure -odium taurocholate were satisfactory for this purpose. The pH optimum for controls, Gaucher disease carriers and Gaucher disease patients was 5.4 using citrate-phosphate buffer. Although leukocytes prepared from only a small amount of blood (2-8 ml) are required, there is sufficient quantity for measuring other lysosomal enzymes as controls. Using this method, 12 patients with all types of Gaucher’s disease and 12 obligate hetero- zygotes were identified. Carrier status was predicted in six other family members and ruled out in six others. Eight unaffected people married to Gaucher carriers or Gaucher patients were predicted to’ be non-carriers of Gaucher’s disease, thereby ruling out children affected with Gaucher’s disease in that mating. Received zyxwvutsrqp 31 May, revised 31 August, uccrpted for publication 9 Septemhcr zyx 1,077 Gaucher’s disease is an autosomal recessive disease which can present in at least three clinical forms. The most common adult or non-neuropathic form (Type 1) can be clinically recognized early in life or after several decades of normal development. Enlargement of the spleen, anemia and possible bone changes are usually present, although neurologic symptoms are not found. This form occurs most frequently in families of Ashkenazi Jewish ancestry. The infantile form or acute neuropathic form (Type 2) is often recognized within the first few months of life because of the massive splenomegaly and developmental problems resulting in severe mental retarda- tion and death within the first year or two. The juvenile form or subacute neuropathic zy : A portion of this material has been submitted in partial fulfillment of the requirements for the Master of Science degree.