Inclusion Criteria:  Must provide written or electronic consent after the nature of the study has been explained, and prior to any research-related procedures, per International Conference on Harmonisation (ICH) Good Clinical Practice (GCP) Clinical diagnosis of PXE supported by prior genetic identification of biallelic Abcc6 mutations Male or female, 18 to <65 years of age at Screening Plasma PPi <1300 nM at Screening Subjects who are being treated with statins or proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors must be on stable doses for 3 years prior to enrollment and be planning to maintain stable doses through end of study unless the investigator deems, in consultation with the sponsor, that the change will not confound interpretation of the study data Women of child-bearing potential (WOCBP) as defined in Clinical Trials Facilitation and Coordination Group (CTFG 2020) must have a negative serum pregnancy test at Screening WOCBP and partners of fertile males who are WOCBP must be using or agree to use one highly effective form of contraception (per CTFG 2020) and a barrier method from at least 1 month before the first dose of INZ-701 through 30 days after last dose of INZ-701 (greater than 5 half-lives of INZ-701). WOCBP and partners of fertile males who are WOCBP must also agree to not donate ova from the period following the first dose of INZ-701 through 30 days after last dose of INZ-701. Males who are sexually active must agree to use condoms from the period following first dose of INZ-701 through 30 days after the last dose of INZ-701. Males must also agree to not donate sperm from the period following the first dose of INZ-701 through 30 days after last dose of INZ-701. In the opinion of the Investigator, must be willing and able to complete the Dose Evaluation Period Agree to provide access to relevant medical records  Exclusion Criteria:  In the opinion of the Investigator, presence of any clinically significant disease (outside of those considered associated with the diagnosis of ABCC6 Deficiency) that precludes study participation or may confound interpretation of study results, including known uncontrolled thyroid disease or unrelated connective tissue, bone, mineral, ophthalmologic, or muscle disease At high risk for sudden blindness (eg, blood in the macula, and/or retinal bleeding, and/or uncontrolled choroidal neovascularization [CNV], and/or visual acuity of less than 20/70 at Screening. Blindness is not an exclusion.)  Clinically significant abnormal laboratory result at Screening in the opinion of the Investigator including but not limited to screening laboratory results demonstrating  eGFR <60 mL/min/1.73m2 (CKD-EPI equation), 25 hydroxyvitamin D (25[OH]D) levels <20 ng/mL, parathyroid hormone (PTH) >40% above the upper limit of normal, or calcium outside of the laboratory reference range; however, minor deviations from the normal range may not be exclusionary if considered to be not clinically significant by the Investigator. Known active fungal, bacterial, and/or viral infection including including human immunodeficiency virus, hepatitis B virus, hepatitis C virus, or COVID-19 infection. A negative COVID-19 test result is required within 5 days prior to first dose of INZ-701. Malignancy within the last 5 years, except non-melanoma skin cancers or cervical carcinoma in situ Known intolerance to INZ-701 or any of its excipients  Unable or unwilling to discontinue the use of any prohibited medication.  Examples:  Calcimimetics (no use within 3 months prior to initiation of the study) Systemic corticosteroids ≥5 mg prednisone equivalent per day (no use for more than 14 days within 3 months prior to initiation of study) Systemic oral or transdermal estrogen (use for contraception is allowed), selective estrogen receptor modulators (SERMs), hormone ablation therapy, tibolone (no more than 1 month of cumulative use within 6 months prior to initiation of the study) Biologic bone modulators (no use within 18 months prior to initiation of study) Oral bisphosphonates (no use within the past 2 years prior to initiation of study) Intravenous (IV) bisphosphonates: Zoledronic acid (no use within 3 years prior to initiation of study, no more than 1 dose received within 3 to 5 years prior to initiation of study); Ibandronate or pamidronate (no use within 12 months prior to initiation of study, no more than 1 month of cumulative use within 3 years prior to initiation of the study, no more than 3 years of cumulative use, unless last dose received ≥5 years prior to initiation of study) Calcium supplements - including antacids containing calcium (no use within 36 hours of the first dose of study drug) Pyrophosphate containing medications (no use within 14 days prior to initiation of study) Concurrent participation in another non-Inozyme clinical study and/or receipt of any other investigational new drug within 5 half-lives of the last dose of the other investigational drug or from 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 Last symptoms from a COVID-19 vaccination within 14 days prior to the first dose of INZ-701 or as described in Inozyme COVID-19 Vaccine Guidance Document Subjects who are pregnant, trying to become pregnant, or breastfeeding Subjects who are trying to father a child