Natural History Study of Homocystinuria Caused by Cystathionine Beta-Synthase Deficiency (ACAPPELLA)

Inclusion Criteria: * Patients who are clinically diagnosed with homocystinuria * Male/female patients aged 1 to 65 years * Patients who consented and/or assented * Patients who are willing and able to comply with all study-related procedures. Exclusion Criteria: * Medically significant postnatal complications or congenital anomalies that are not associated with homocystinuria * Received any experimental therapy for homocystinuria during the 6 months prior to enrollment or expected to receive any such therapy during duration of the study