The study will evaluate the safety and efficacy of Replagal® (agalsidase alfa) at a dose of 0.2 mg/kg infused intravenously (IV) over 40 minutes, every other week. The study will monitor the course of disease in males and females with Fabry disease who are naive to treatment or were previously treated with agalsidase beta (Fabrazyme®).

This study will evaluate the safety and efficacy of Replagal in patients with Fabry disease who are either naive to treatment, who were previously treated with agalsidase beta, or who had previously received Replagal.

Patients diagnosed with Fabry disease who have not previously received treatment, who have received agalsidase beta, or who had previously received Replagal will be eligible to enroll in the study and will receive Replagal at a dose of 0.2 mg/kg body weight administered by an IV infusion over 40 minutes every other week.

This study will be conducted in the United States.

Study visits will occur in 3 phases:

• Screening/Baseline Phase: A Screening/Baseline period (Day -30 to Day -1) to determine eligibility and obtain baseline measurements. Patients who have previously received agalsidase beta will be tested for the presence of anti-agalsidase beta antibodies.
• Treatment Phase: A 12-month treatment phase during which all patients will receive Replagal administered IV every other week. Clinical assessments will occur at Months 1, 3, 6, 9, and 12. The study may be extended to continue giving patients access to treatment.
• End-of-Study Phase: An end-of-study contact either as an office visit or follow-up telephone call will occur one month after the last infusion.

Inclusion Criteria:

1. Confirmed diagnosis of Fabry disease.
2. Patient is willing and able to provide written informed consent, and assent if applicable.
3. Females of childbearing potential must agree to use a method of birth control throughout the study and for at least 30 days after the final infusion. The method of contraception must be considered adequate and appropriate in the opinion of the investigator.

Exclusion Criteria:

1. Hypersensitivity to Replagal, the active substance, or any of the excipients.
2. The patient is pregnant or breast feeding.
3. Concomitant use of agalsidase beta (Fabrazyme).
4. Has received treatment with any investigation drug or device within the 30 days prior to study entry.
5. Otherwise unsuitable for the study, in the opinion of the Investigator.