Only two Gaucher disease (GD) patients bearing mutations in the prosaposin gene (PSAP), and not in the glucocerebrosidase gene (GBA), have been reported. In both cases, one mutant allele remained unidentified. We report here the identification of the second mutation in one of these patients, being the first complete genotype described so far in a SAP-C-deficient GD patient. This mutation, p.Q430X, is the first one reported in the saposin D domain and probably produces a null allele by nonsense mediated mRNA decay.