Inclusion Criteria:

1. Caregiver(s) must provide written or electronic consent after the nature of the study has been explained, and prior to any research-related procedures, per International Council for Harmonisation (ICH) Good Clinical Practice (GCP)
2. Study participant must have a confirmed post-natal molecular genetic diagnosis of ENPP1 Deficiency or ABCC6 Deficiency with biallelic mutations (ie, homozygous or compound heterozygous) performed by a College of American Pathologists/Clinical Laboratory Improvement Amendments (CAP/CLIA) certified laboratory
3. Study participants must have clinical manifestations of GACI or GACI-2, which may include, but are not limited to, pathologic ectopic calcification, heart failure, respiratory distress, edema, cyanosis, hypertension, and cardiomegaly
4. Study participant must be male or female from birth to <1 year of age at Baseline (Day 1)
5. Study participant must weigh ≥0.5 kg at the time of the first dose of INZ-701 in this study
6. In the opinion of the Investigator, the study participant must be able to complete all aspects of the study
7. Study participant's caregiver(s) must agree to provide access to their child's relevant medical records

Exclusion Criteria:

1. In the opinion of the Investigator, presence of any clinically significant disease or laboratory abnormality (outside of those considered associated with the diagnosis of ENPP1 Deficiency or ABCC6 Deficiency) that precludes study participation or may confound interpretation of study results, including known uncontrolled thyroid disease or unrelated connective tissue, bone, mineral, or muscle disease
2. Care has been withdrawn or study participant is receiving end of life care or hospice only
3. Known malignancy
4. Known intolerance to INZ-701 or any of its excipients
5. Concurrent participation in another non-Inozyme interventional study
6. Receipt of any non-Inozyme investigational new drug within 5 half-lives of the last dose of the other investigational product or within 4 weeks prior to the first dose of INZ-701, whichever is longer, or use of an investigational device, through completion of participation in the study