A Retrospective, Observational, Noninterventional Data Collection Study for Patients With Molybdenum Cofactor Deficiency Who Have Been Previously Treated With Cyclic Pyranopterin Monophosphate (cPMP)

Inclusion Criteria:

1. Male or female of any age.

2. Patient with MoCD type A, suspected type A, or type B.

3. Patient previously received cPMP only by intravenous route of administration.

4. Parent(s) or legal guardian(s), depending on local regulations, has voluntarily
provided written informed consent for the Investigator, Investigator's designee, or
Sponsor designee to review, collect, transmit, and analyze data extracted from the
medical record. In the case of a deceased patient for whom the parents or legal
guardians could not be located, the appropriate ethical review committee may assign
another person as legal representative to provide consent, where applicable per local
and country regulations.

Exclusion Criteria:

- Patient's parent(s) or legal guardian(s) are unable to understand the nature and scope
of the study.