Open-Label Extension Study of the Long-Term Effects of Migalastat HCL in Patients With Fabry Disease

Inclusion Criteria:

- Subject had completed treatment in a previous study of migalastat HCl

- Age 18 years or older

- Male and female participant agrees to use protocol identified acceptable contraception

- Subject is willing to provide written informed consent and authorization for use and
disclosure of Personal Health Information (PHI)

Exclusion Criteria:

- Subjects last available estimated glomerular filtration rate (eGFR) in the previous
study was <30 mL/min/1.73m2; unless there is measured GFR available within 3 months of
Baseline Visit (Visit 1), which is >30 mL/min/1.73m2

- Subject has undergone, or is scheduled to undergo kidney transplantation or is
currently on dialysis

- Subject has a documented transient ischemic attack, stroke, unstable angina, or
myocardial infarction within the 3 months before Visit 1

- Subject has clinically significant unstable cardiac disease in the opinion of the
investigator (e.g., cardiac disease requiring active management, such as symptomatic
arrhythmia, unstable angina, or NYHA class III or IV congestive heart failure)

- Subject has a history of allergy or sensitivity to AT1001 (including excipients) or
other iminosugars (e.g., miglustat, miglitol)

- Subject requires treatment with Glyset® (miglitol) or Zavesca® (miglustat)

- Subjects with severe or unsuitable concomitant medical condition

- Subjects with clinically significant abnormal laboratory value(s) and clinically
significant electrocardiogram (ECG) findings at baseline