Genotype assignment in Gaucher disease by selective amplification of the active glucocerebrosidase gene.

Genomic DNA prepared from human cells in culture was amplified by the polymerase chain-reaction technique using two primers specific for the active human glucocerebrosidase gene. The 1,036-bp amplified fragment derived from the active gene was tested for the existence of three mutations--designated "370," "NciI," and "HhaI"--by allele-specific oligonucleotide hybridization. The results obtained from the cell lines examined permitted a clear distinction between homozygous affected, heterozygous, and normal genotypes. However, 28% of the possible affected loci were normal with respect to the three mutations, indicating the presence of additional mutations that remain to be elucidated. While the NciI mutation could be found in both Ashkenazi Jewish and non-Jewish type 1 patients, the only homozygotes with this mutation had the neurological (type 2 or type 3) form of the disease. The 370 mutation, on the other hand, was only present in type 1 patients and was not identified among any of the patients with neurologic forms of the disease.