To date, the investigators lack characterization of, the burden of, and the systemic progression of disease in ENPP1 deficiency and ABCC6 deficiency from a patient and/or parent perspective. This study aims to document this characterization, progression as well as the burden of disease. Link to the study registration-

https://www.engagehealth.com/survey/TakeSurvey.aspx?SurveyID=8252n62

This will be a comprehensive, cross-sectional study conducted in approximately 60 individuals (or representative parents of patients) affected by ENPP1 deficiency and the acute form of ABCC6 deficiency. All study participants will complete the RSVP, PRO tools and upload a proof of disease form, followed by an interview conducted by a trained interviewer. It is estimated that each respondent will need up to 60 minutes for the entire process; 20 minutes to complete the RSVP, PRO tools and to upload proof of diagnosis of ENPP1 deficiency or the acute form of ABBC6 deficiency, and approximately 40 minutes to complete the interview and address any follow-up questions if needed.

Inclusion Criteria:

1. Participant must be a person with ENPP1 deficiency or the acute infantile form of ABCC6 deficiency who is 18 years or older
2. The parent/caregiver of a patient who has been diagnosed with ENPP1 deficiency or the acute infantile form of ABCC6 deficiency. Please note, parents/caregivers of patients with ENPP1 deficiency who have passed away may participate
3. Confirmed diagnosis of ENPP1 deficiency or ABCC6 deficiency with written proof of disease provided
4. Ability to participate in the RSVP and interview in German, French or English, irrespective of country of residence.
5. Able to grant informed consent
6. Willing to participate in a 40-to-60-minute telephone interview, including follow up questions (if necessary)

Exclusion Criteria:

• Inability to meet any of the inclusion criteria

60 participants across four groups; person or parent/legal guardian affected by ENPP1 (GACI or ARHR2) or the acute form of ABCC6 def. described below;

• Acute infantile ENPP1 def. (due to the high infant mortality, this group likely to include parents of affected children, both living and deceased)
• Acute infantile ABCC6 def. (due to the high infant mortality, this group likely to include parents of affected children, both living and deceased)
• Progressive pediatric ENPP1 def. who are still growing (note; due to the age of those who are still growing, this group is likely to include parents of affected children)
• Adult ENPP1 def. who are no longer growing (note: due to the age of those who are no longer growing, this group is likely to include both patients > age 18 years and parents of affected children who are < age 18 years or who are unable to answer for themselves)