A sample obtained from an individual who meets all the appropriate eligibility criteria for either GACI or ARHR2 as follows:
For individuals suspected of having GACI:
- If a plasma or urine PPi result is available, the result is less than 50% of normal.
- The individual has serious or life-threatening symptoms (as listed in the last line of this list below) within the first 6 months of life, and if currently older than 6 months of age, had a peak in their serious or life-threatening symptoms within the first 6 months of life.
- The individual has or has had arterial calcifications within the first 6 months of life for which twin-to-twin transfusion and sickle cell anemia has been excluded as the cause.
- The individual has or has had hypertension, respiratory difficulties, cardiac insufficiency, myocardial infarction (MI), or failure to thrive (FTT) within the first 6 months of life.
For individuals suspected of having ARHR2:
- If a plasma or urine PPi result is available, the result is less than 50% of normal.
- The individual has a current or past clinical diagnosis of rickets.
- Other causes of rickets, other than ENPP1 mutations, have been excluded including, but not limited to, Vitamin D deficiency, and genetic mutations in other genes known to cause rickets including the FGF23, PXE, and DMP1 genes.