ARPKD Known PKHD1 Variant Prenatal Testing (PT2)
Information for Ordering
Acceptable Specimen Types
- Maternal blood sample: 3–6 mL EDTA, submitted with or before the prenatal specimen for maternal cell contamination studies. Delayed receipt may delay turnaround time.
- Direct chorionic villus sampling specimen: minimum of 10 mg of pure villi
- Direct amniotic fluid: minimum of 10 mL
- Two T25 flasks of cultured chorionic villus cells: greater than 70% confluent
- Two T25 flasks of cultured amniocytes: greater than 70% confluent
Cultured cells are required for targeted analysis of known multi-exon deletions or duplications.
Turnaround Time
- Prenatal testing: 6 working days
Price, CPT Codes, and Z Code
- Institutional/self-pay price: $1,000 USD
- CPT codes: 81265 and 81403 × 2
- Z code: ZB67M
Candidates for Testing
Testing is offered to established patients and families with previously identified pathogenic variants in PKHD1 who are pursuing prenatal or preimplantation genetic testing or testing for individuals at risk of inheriting a known familial variant.
Specimen Shipping and Handling
Please refer to the specimen requirements listed above.
Maternal blood, direct prenatal specimens, and cultured-cell specimens should be shipped at room temperature unless otherwise directed by the laboratory. Do not ship specimens on ice.
Specimens must be packaged to prevent breakage. Absorbent material must be included to contain liquids if breakage occurs. Specimens must also be shipped in double watertight containers, such as a specimen pouch placed inside the shipping company’s diagnostic envelope.
To request a collection kit, please complete the Collection Kit Request Form.
Before shipping a specimen, please contact the UAB Medical Genomics Laboratory by email at medgenomics@uabmc.edu or by phone at 205-934-5562. Please provide the specimen type, collection date, shipment date, and package tracking number so the laboratory can help ensure proper and timely receipt.
Required Forms
About
Disorder Background
Autosomal recessive polycystic kidney disease is characterized by enlarged cystic kidneys and hepatic fibrosis. The diagnosis is often made prenatally or during the neonatal period, although some patients are diagnosed later in life. Disease severity varies widely, and mortality is high during the first months of life in the most severely affected patients.
ARPKD is one of the more common hereditary childhood nephropathies, with an estimated incidence of approximately 1 in 20,000–40,000 individuals. The estimated carrier frequency in the general population is approximately 1 in 70 to 1 in 100.
The PKHD1 gene, also known as Polycystic Kidney and Hepatic Disease 1, is located on chromosome 6p21-p12 and spans approximately 470 kb of genomic DNA. It is the only gene known to be associated with the broad clinical spectrum of autosomal recessive polycystic kidney disease.
More than 80 exons and multiple alternative transcripts have been identified. Pathogenic variants include missense, nonsense, frameshift, splice-site, and multi-exon deletion variants. Variants are distributed throughout the gene, and most affected families carry private familial variants.
Test Description
The ARPKD Known PKHD1 Variant Prenatal Test provides targeted detection of one or more previously characterized familial pathogenic variants.
DNA is extracted from the submitted prenatal specimen, and the target region is amplified and analyzed by direct Sanger sequencing. Maternal cell contamination studies are performed using the accompanying maternal blood specimen.
Cultured prenatal cells are required when targeted analysis involves a known multi-exon deletion or duplication.
To offer this testing service, the familial pathogenic variants must have been identified previously by the UAB Medical Genomics Laboratory.
View references for this testing.
Other Related Test Options
- ARPKD Known PKHD1 Variant Linkage Analysis for Informativity (PKDL) and Prenatal Linkage Analysis (PKDPL)
- ARPKD Known PKHD1 Variant Testing (KT2)
For more information, test requisition forms, or collection kits, please contact the UAB Medical Genomics Laboratory at 205-934-5562 or medgenomics@uabmc.edu.