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  • Test code: 72038
  • Turnaround time:
    10–21 calendar days (14 days on average)
  • Preferred specimen:
    3mL whole blood in a purple-top EDTA tube (K2EDTA or K3EDTA)
  • Alternate specimens:
    Saliva, assisted saliva, buccal swab and gDNA
  • Sample requirements
  • Request a sample kit
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Invitae X-Linked Hypophosphatemia Test

Test description

The Invitae X-Linked Hypophosphatemia Test analyzes the PHEX gene, which is associated with the most common genetic form of hypophosphatemia.

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Primary panel (1 gene)
  • X-linked hypophosphatemia (XLH)

To view the complete clinical description of this panel, click here.

X-Linked Hypophosphatemia is inherited as an X-linked dominant condition.

  1. Chesher, D, et al. Outcome of adult patients with X-linked hypophosphatemia caused by PHEX gene mutations. J. Inherit. Metab. Dis. 2018; 41(5):865-876. PMID: 29460029
  2. Fuente, R, et al. X-linked hypophosphatemia and growth. Rev Endocr Metab Disord. 2017; 18(1):107-115. PMID: 28130634
  3. Beck-Nielsen, SS, et al. Incidence and prevalence of nutritional and hereditary rickets in southern Denmark. Eur. J. Endocrinol. 2009; 160(3):491-7. PMID: 19095780
  4. Acar, S, et al. Clinical and genetic characteristics of 15 families with hereditary hypophosphatemia: Novel Mutations in PHEX and SLC34A3. PLoS ONE. 2018; 13(3):e0193388. PMID: 29505567
  5. Beck-Nielsen, SS, et al. Mutational analysis of PHEX, FGF23, DMP1, SLC34A3 and CLCN5 in patients with hypophosphatemic rickets. J. Hum. Genet. 2012; 57(7):453-8. PMID: 22695891
  6. Ruppe, MD. X-Linked Hypophosphatemia. 2012 Feb 09. In: Adam, MP, et al, editors. GeneReviews® (Internet). University of Washington, Seattle. PMID: 22319799
  7. Bitzan, M, Goodyer, PR. Hypophosphatemic Rickets. Pediatr. Clin. North Am. 2019; 66(1):179-207. PMID: 30454743
  8. Cagnoli, M. Spontaneous growth and effect of early therapy with calcitriol and phosphate in X-linked hypophosphatemic rickets. Pediatr Endocrinol Rev. 2017; 15(Suppl 1):119-122 PMID: 29292875
  9. Lyseng-Williamson, KA. Burosumab in X-linked hypophosphatemia: a profile of its use in the USA. Drugs Ther Perspect. 2018; 34(11):497-506. PMID: 30459508
  10. Capelli S, et al. Clinical and molecular heterogeneity in a large series of patients with hypophosphatemic rickets. Bone. 2015; 79:143-9. PMID: 26051471
  11. Carpenter, TO, et al. A clinician's guide to X-linked hypophosphatemia. J. Bone Miner. Res. 2011; 26(7):1381-8. PMID: 21538511

Assay and technical information

Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).

Our sequence analysis covers clinically important regions of each gene, including coding exons and 10 to 20 base pairs of adjacent intronic sequence on either side of the coding exons in the transcript listed below. In addition, the analysis covers the select non-coding variants specifically defined in the table below. Any variants that fall outside these regions are not analyzed. Any limitations in the analysis of these genes will be listed on the report. Contact client services with any questions.

Based on validation study results, this assay achieves >99% analytical sensitivity and specificity for single nucleotide variants, insertions and deletions <15bp in length, and exon-level deletions and duplications. Invitae's methods also detect insertions and deletions larger than 15bp but smaller than a full exon but sensitivity for these may be marginally reduced. Invitae’s deletion/duplication analysis determines copy number at a single exon resolution at virtually all targeted exons. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. Certain types of variants, such as structural rearrangements (e.g. inversions, gene conversion events, translocations, etc.) or variants embedded in sequence with complex architecture (e.g. short tandem repeats or segmental duplications), may not be detected. Additionally, it may not be possible to fully resolve certain details about variants, such as mosaicism, phasing, or mapping ambiguity. Unless explicitly guaranteed, sequence changes in the promoter, non-coding exons, and other non-coding regions are not covered by this assay. Please consult the test definition on our website for details regarding regions or types of variants that are covered or excluded for this test. This report reflects the analysis of an extracted genomic DNA sample. In very rare cases, (circulating hematolymphoid neoplasm, bone marrow transplant, recent blood transfusion) the analyzed DNA may not represent the patient's constitutional genome.

Gene Transcript reference Sequencing analysis Deletion/Duplication analysis
PHEX* NM_000444.5

PHEX: Analysis includes the NM_000444.5:c.*231A>G variant.