Rickets, Hypophosphatemic, Autosomal Dominant

Affected individuals have hypophosphatemia and bone mineralization defects that result in rickets,osteomalacia with bone pain, lower extremity deformities, and muscle weakness. Dental abscesses are prevalent. The disorder is resistant to treatment with Vitamin D. ADHR is phenotypically similar to the more common X-linked form caused by mutation in the PHEX gene; however, it may demonstrate greater clinical variability with incomplete penetrance and delayed onset. In addition, as this is an autosomal dominant condition, male-to-male transmission occurs. Homozygous mutation in FGF23 has also been reported in hyperphosphatemic tumoral calcinosis (MIM 211900), a rare autosomal recessive disorder characterized by the progressive deposition of calcified masses in cutaneous and subcutaneous tissues and elevated circulating levels of phosphate, also due to mutation in GALNT3.

Tests Available

Forms and Documents

Test Details

FGF23
  • Confirmation of the clinical diagnosis
  • Differentiation between X-linked and dominant forms of the disease
  • Determination of appropriate therapeutic approach
  • Prenatal diagnosis in at-risk pregnancies
  • Capillary Sequencing

Ordering

184
3 weeks
2-5 mL Blood - Lavender Top Tube
Oral Rinse (30-40 mL)|Dried Blood Spots|Buccal Swabs

Billing

81404x1
Yes
Yes
  • 275.4 Disorders of calcium metabolism
  • 275.3.1 Multiple epiphyseal dysplasia
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References

  1. Chefetz, I et al., A novel homozygous missense mutation in FGF23 causes Familial Tumoral Calcinosis associated with disseminated visceral calcification Hum Genet 118(2):261-266 (2005)
  2. Jan, SM et al., Perspective: Molecular Pathogenesis of Hypophosphatemic Rickets J Clin Endocrin & Metab 87(6):2467-2473 (2002)
  3. White, KE and Lorenz-Depiereux, B, et al. (The ADHR Consortium), Autosomal dominant hypophosphatemic rickets is associated with mutations in FGF23 Nat Genet 26:345-348 (2000)