Test ID: ARPKZ Autosomal Recessive Polycystic Kidney Disease, Full Gene Analysis, Varies
Useful For
Diagnosis of individuals suspected of having autosomal recessive polycystic kidney disease (ARPKD)
Prenatal diagnosis if there is a high suspicion of ARPKD based on ultrasound findings
Carrier testing of individuals with a family history of ARPKD, but an affected individual is not available for testing or disease-causing variants have not been identified
Reflex Tests
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
CULFB | Fibroblast Culture for Genetic Test | Yes | No |
CULAF | Amniotic Fluid Culture/Genetic Test | Yes | No |
MATCC | Maternal Cell Contamination, B | Yes | No |
Testing Algorithm
For prenatal specimens only: If amniotic fluid (nonconfluent cultured cells) is received, amniotic fluid culture/genetic test will be added and charged separately. If chorionic villus specimen (nonconfluent cultured cells) is received, fibroblast culture for genetic test will be added and charged separately. For any prenatal specimen that is received, maternal cell contamination studies will be added.
Special Instructions
Method Name
Custom Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing when appropriate
Reporting Name
ARPKD Full Gene AnalysisSpecimen Type
VariesAdditional Testing Requirements
All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.
Shipping Instructions
Whole blood specimens preferred to arrive within 96 hours of collection.
Specimen Required
Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Additional Information: To ensure minimum volume and concentration of DNA is met, the preferred volume of specimen must be submitted. Testing may be canceled if DNA requirements are inadequate.
Submit only 1 of the following specimens:
Specimen Type: Whole blood
Container/Tube:
Preferred: Lavender top (EDTA) or yellow top (ACD)
Acceptable: Any anticoagulant
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send specimen in original tube. Do not aliquot.
Specimen Stability Information: Ambient (preferred)/Refrigerated
Prenatal Specimens
Due to the complexity of prenatal testing, consultation with the laboratory is required for all prenatal testing.
Specimen Type: Amniotic fluid
Container/Tube: Amniotic fluid container
Specimen Volume: 20 mL
Specimen Stability Information: Refrigerated (preferred)/Ambient
Specimen Type: Chorionic villi
Container/Tube: 15-mL tube containing 15 mL of transport media
Specimen Volume: 20 mg
Specimen Stability Information: Refrigerated
Acceptable:
Specimen Type: Confluent cultured cells
Container/Tube: T-25 flask
Specimen Volume: 2 Flasks
Collection Instructions: Submit confluent cultured cells from another laboratory.
Specimen Stability Information: Ambient (preferred)/Refrigerated
Specimen Minimum Volume
Blood: 1 mL
Amniotic Fluid: 10 mL
Chorionic Villi: 5 mg
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Varies |
Clinical Information
Autosomal recessive polycystic kidney disease (ARPKD) is a disorder caused by variants in the polycystic kidney and hepatic disease 1 (PKHD1) gene. The incidence of ARPKD is approximately 1:20,000 and the estimated carrier frequency in the general population is 1:70. ARPKD is characterized by enlarged echogenic kidneys, congenital hepatic fibrosis, and pulmonary hypoplasia (secondary to oligohydramnios [insufficient volume of amniotic fluid] in utero). Most individuals with ARPKD present during the neonatal period and, of those, nearly one-third die of respiratory insufficiency. Early diagnosis, in addition to initiation of renal replacement therapy (dialysis or transplantation) and respiratory support, increases the 10-year survival rate significantly. Presenting symptoms include bilateral palpable flank masses in infants and subsequent observation of typical findings on renal ultrasound, often within the clinical context of hypertension and prenatal oligohydramnios. In rarer cases, individuals may present during childhood or adulthood with hepatosplenomegaly. Of those who survive the neonatal period, one-third progress to end-stage kidney disease and up to one-half develop chronic kidney insufficiency.
The PKHD1 gene maps to 6p12 and includes 67 exons. The PKHD1 gene encodes a protein called fibrocystin, which is localized to the primary cilia and basal body of renal tubular and biliary epithelial cells. Because ARPKD is an autosomal recessive disease, affected individuals must carry 2 deleterious variants within the PKHD1 gene. Although disease penetrance is 100%, intrafamilial variation in disease severity has been observed. Variant detection is often difficult due to the large gene size and the prevalence of private variants that span the entire length of the gene.
Reference Values
An interpretive report will be provided.
Interpretation
All detected alterations are evaluated according to American College of Medical Genetics and Genomics (ACMG) recommendations.(1) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.
Clinical Reference
1. Richards S, Aziz N, Bale S, et al: Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med 2015 May;17(5):405-424. doi: 10.1038/gim.2015.30
2. Guay-Woodford LM, Desmond RA: Autosomal recessive polycystic kidney disease: the clinical experience in North America. Pediatrics. 2003;111:1072-1080. doi: 10.1542/peds.111.5.1072
3. Guay-Woodford LM, Bissler JJ, Braun MC, et al: Consensus expert recommendations for the diagnosis and management of autosomal recessive polycystic kidney disease: Report of an international conference. J Pediatr. 2014 Sep;165(3):611-617. doi: 10.1016/j.jpeds.2014.06.015
4. Gunay-Aygun M, Avner E, Bacallao RL, et al: Autosomal recessive polycystic kidney disease and congenital hepatic fibrosis: summary of a first National Institutes of Health/Office of Rare Diseases conference. J Pediatr. 2006;149:159-164. doi: 10.1016/j.jpeds.2006.03.014
5. Harris PC, Rossetti S: Molecular genetics of autosomal recessive polycystic kidney disease. Mol Genet Metab. 2004;81:75-85. doi: 10.1016/j.ymgme.2003.10.010
Day(s) Performed
Varies
Report Available
14 to 20 daysTest Classification
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81408
Fibroblast Culture for Genetic Test
88233-(if appropriate)
88240-(if appropriate)
Amniotic Fluid Culture/Genetic Test
88235-(if appropriate)
88240-(if appropriate)
Maternal Cell Contamination, B
81265-(if appropriate)
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
ARPKZ | ARPKD Full Gene Analysis | 94226-8 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
53449 | Result Summary | 50397-9 |
53450 | Result | 82939-0 |
53451 | Interpretation | 69047-9 |
53452 | Additional Information | 48767-8 |
53453 | Specimen | 31208-2 |
53454 | Source | 31208-2 |
53455 | Released By | 18771-6 |
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available in Special Instructions:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Molecular Genetics: Congenital Inherited Diseases Patient Information (T521) in Special Instructions
3. If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
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