Infantile Hypercalcemia

Gene: CYP24A1

Protein: 1,25-dihydroxyvitamin D(3) 24-hydroxylase, mitochondrial

Clinical Characteristics

  • Hypercalcemia, symptoms include:
    • Failure to thrive
    • Vomiting
    • Dehydration
    • Nephrocalcinosis
    • Nephrolithiasis
  • Hypercalciuria
  • Suppressed intact PTH
  • Variable age of onset:
    • Severe form presents in infancy
    • Mild to severe symptoms presenting in adulthood

Inheritance pattern: Autosomal recessive; carriers with either subclinical biochemical phenotypes or clinical symptoms have been reported

What Can Be Learned From This Test

Testing is performed by sequencing coding exons 1-11, and a portion of exon 12 in the 3’UTR. This test will detect point mutations, small deletions and small insertions. The gene dosage assay will detect some partial and all whole gene deletions or duplications. Large deletions and duplications in CYP24A1 have not been reported.

Common pathogenic variants have been reported in exons 2, 3, 6, 7, 9. Partial sequencing in regions known to carry mutations can be carried out and may be ordered as Tier 1 testing; please note on submission form if this tiered approach is being requested.

Sample Requirements

Draw 2ml–4ml of blood in EDTA/purple-top tube (minimum of 1ml–2ml for infants).

Turnaround time: 10-14 business days

CPT Codes and Cost

Full Gene Sequencing & Gene Dosage

  • Code: 81479
  • Cost: $800

Tier 1: Exons 2, 3, 6, 7, 9 Only

  • Code: 81479
  • Cost: $350

Tier 2: Sequencing Remaining Exons & Gene Dosage

  • Code: 81479
  • Cost: $450

Known Variant Testing

  • Code: 81479
  • Cost: $225

Additional Information