Pharmacokinetics, Safety and Tolerability of Zavesca (Miglustat) in Patients With Infantile Onset Gangliosidosis: Single and Steady State Oral Doses

Inclusion criteria 1. Diagnosis of GM2 gangliosidosis, confirmed by demonstration of profound deficiency of -hexosaminidase A or A \& B in peripheral blood leukocytes or in cultured skin fibroblasts, within the previous 1 year in non-bone marrow transplant recipients who are \< 2 years of age, or prior to stem cell transplant in stably engrafted transplant patients who are \< 5 years of age. 2. Onset of characteristic clinical symptoms of the disease before the age of 9 months. 3. Normal renal and hepatic function. 4. Written informed consent from parent or legal guardian. Exclusion criteria 1. Patients who are unable to comply with the study procedures of this protocol, including the refusal to swallow the food used to mask the taste of the study drug and whose parents are unwilling to administer the drug through a nasogastric or gastrostomy tube. 2. Patients receiving other investigational agents within 3 months of study initiation. 3. Patients who are anemic (hemoglobin \< 11 g/dl, and/or hematocrit \< 34%) 4. Patients who have a history of significant gastrointestinal disorders, including clinically significant diarrhea (\>3 liquid stools per day for \> 7 days), without definable cause within 3 months of baseline visit. 5. Patients with a high probability of dying during the 6-month assessment period of the study. 6. Patients who in the opinion of the investigator (for whatever reason) are thought to be unsuitable for the study.