Registry of Patients With Hypophosphatasia

Inclusion Criteria: * Male and female participants, of any age, with a confirmed diagnosis of HPP. * Participant must have documented alkaline phosphatase (ALP) activity below the lower limit of normal for age and sex, or a documented ALPL gene mutation. * Participant or legal representative is able to read and/or understand the informed consent and study questionnaires in the local language. * Signed informed consent and medical records release by the patient or legal representative. Patient or patient's parent/legal representative must be willing and able to give written informed consent, and the patient must be willing to give written informed assent, if appropriate and required by local regulations. Exclusion Criteria: * Currently participating in an Alexion-sponsored clinical trial. Enrollment in the Registry will not exclude a patient from enrolling in a future clinical trial.