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Primary Hyperoxaluria Type 1 Test
Patients with primary hyperoxaluria (PHO) type I have a defect in the liver-specific enzyme alanine-glyoxylate aminotransferase encoded by AGXT. Patients accumulate oxalate, and calcium oxalate deposits lead to urolithiasis, nephrocalcinosis and ultimately renal failure. Other organs may be damaged as well. Age of onset can vary widely from the first year to the third decade of life.
Missense mutations may be associated with milder clinical and biochemical phenotypes
Next Generation Sequencing (NGS) of the coding regions and intron-exon boundaries of AGXT; Deletion/Duplication: Dosage analysis by normalization of NGS read depth for AGXT; Sanger sequencing for potential fill in / confirmation
This test is also available as part of one or more NGS panels for peroxisomal disorders
Identification of causative mutations in known or suspicious cases of PHO; rule-out in the presence of equivocal clinical presentation and/or biomarker profile; targeted carrier testing of relatives of proband; predictive prenatal testing when familial mutations are known.
Primary hyperoxaluria is divided into two types. By definition, type 1 is caused by defects in AGXT. Sequence analysis alone will identify two AGXT mutations in >95% of patients with PHO type 1. Deletions or duplications are expected to account for 2-4% of AGXT mutations.
>99% for inherited single nucleotide and small insertion/deletion variants for the nucleotides evaluated; >99% for multi-exon deletions and >98% for single exon deletions; >90% for multi-exon duplications and >75% for single exon duplications. Lower limit of detection for single nucleotide variants: 25% allele frequency (>99% sensitivity).
We prefer whole blood for all tests.
Turn Around Time
Approximately 4 weeks
Fee and CPT Codes
NGS Panel: $2450 for routine testing
CPT Code: 81479
We request that copies of the patient's biochemical analysis be submitted with the sample.
INFORMED CONSENT from the patient is required prior to ordering a genetic test. The DNA Diagnostic Lab's consent is located on the second page of the requisition form. There is also a patient brochure, "Things Every Patient Should Know Before Consenting to a Genetic Test", available for download.