Patients with Type 3 GD exhibit both visceral and neurologic manifestations. In addition to the progressive neurologic involvement, somatic disease manifestations, especially splenomegaly and resulting cytopenia, contribute to significant mortality and morbidity . The effects of enzyme replacement therapy (ERT) on patients with Type 1 GD have been clearly documented and have a beneficial effect on visceral and hematologic disease parameters . It is known that recombinant enzyme does not pass the blood-brain barrier and has no effect on neurologic involvement . Probably due to the rarity of Type 3 GD, information on the somatic effects of ERT is largely limited to case reports or single-center series. There are also few reviews of cohorts but the clinical subtype, age, genotype, ERT dosage, accompanying therapies, and treatment response vary widely among patients in these cohorts. This prospective study aims to objectively evaluate the hematologic and visceral effects of ERT with taliglucerase alfa on a rather clinically and genetically homogenous group of treatment-naïve patients with Type 3 GD . For the purposes of this study, subjects receiving no Gaucher-specific medications for at least 12 months will be considered "untreated". The results of this study are expected to provide a more objective view of the degree of response of this patient type, and potentially create new areas of research.