Analysis and classification of 304 mutant alleles in patients with type 1 and type 3 Gaucher disease

Gaucher disease results from the inherited deficiency of the enzyme glucoce rebrosidase (EC 3.2.1.45). Although >100 mutations in the gene for human gl ucocerebrosidase have been described, most genotype-phenotype studies have focused upon screening for a few common mutations. In this study, we used s everal approaches-including direct sequencing, Southern blotting, long-temp late PCR, restriction digestions, and the amplification refraction mutation system (ARMS)-to genotype 128 patients with type 1 Gaucher disease (64 of Ashkenazi Jewish ancestry and 64 of non-Jewish extraction) and 24 patients with type 3 Gaucher disease. More than 97% of the mutant alleles were ident ified. Fourteen novel mutations (A90T, N117D, T134I, Y135X, R170C, W184R, A 190T, Y304X, A341T, D399Y, c.153-154insTACAGC, c.203-204insC, c.222-224delT AC, and c.1122-1123insTG) and many rare mutations were detected. Recombinan t alleles were found in 19% of the patients. Although 93% of the mutant all eles in our Ashkenazi Jewish type 1 patients were N370S, c.84-85insG, IVS21G-->A or L444P, these four mutations accounted for only 49% of mutant alle les in the non-Jewish type 1 patients. Genotype-phenotype correlations were attempted, Homozygosity or heterozygosity for N370S resulted in type 1 Gau cher disease, whereas homozygosity for L444P was associated with type 3. Ge notype L444P/recombinant allele resulted in type 2 Gaucher disease, and hom ozygosity for a recombinant allele was associated with perinatal lethal dis ease. The phenotypic consequences of other mutations, particularly R463C, w ere more inconsistent. Our results demonstrate a high rate of mutation dete ction, a large number of novel and rare mutations, and an accurate assessme nt of the prevalence of recombinant alleles, Although some genotype-phenoty pe correlations do exist, other genetic and environmental factors must also contribute to the phenotypes encountered, and we caution against relying s olely upon genotype for prognostic or therapeutic judgements.