A CASE OF NONNEUROLOGIC GAUCHERS-DISEASE THAT BIOCHEMICALLY RESEMBLES THE NEUROLOGIC TYPES

Systemic findings such as hepatosplenomegaly and typical Gaucher storage cells in a bone marrow aspirate led to the clinical diagnosis of Gaucher's disease in the seven-year old patient described in this report. On the basis of the lack of neurologic involvement the child was classified as having the Type 1, nonneurologic form of Gaucher's disease. After splenectomy glucocerebrosidase was extracted from her spleen for biochemical analysis. As expected, a marked deficiency of glucocerebrosidase activity was evident in the splenic extract, however her enzyme displayed anomalous behavior compared to other identical splenic preparations from documented Type 1 Gaucher's disease patients in that it failed to reconstitute with the acidic lipid phosphatidylserine. Using the polymerase chain reaction (PCR)-based color complementation assay and restriction endonuclease analysis, we compared the mutation genotype of this child with that of five other classical Type 1 patients. This analysis revealed that our patient alone was homoallelic for a T --> C transition at position 1448 in the glucocerebrosidase cDNA that results in a 444Leu --> Pro substitution in the glucocerebrosidase protein. The latter mutation genotype is normally associated with the neurologic phenotype, namely, the Types 2 and 3 forms of the disease. The relevance of the nature of polarity in clinical and biochemical analyses is discussed with regard to the phenotypic classification and the future clinical course of disease in the child.