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Test ID: ARPKZ Autosomal Recessive Polycystic Kidney Disease (ARPKD), 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 mutations 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.

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 Analysis

Specimen Type

Varies


Additional Testing Requirements


All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis on the maternal specimen.



Shipping Instructions


Whole blood specimens preferred to arrive within 96 hours of collection.

 

Prenatal specimens can be sent Monday through Thursday and must be received by 5 p.m. CST on Friday in order to be processed appropriately.



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.

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
Varies Varies

Clinical Information

Autosomal recessive polycystic kidney disease (ARPKD) is a disorder caused by mutations 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 renal disease and up to one-half develop chronic renal 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 mutations within the PKHD1 gene. Although disease penetrance is 100%, intrafamilial variation in disease severity has been observed. Mutation detection is often difficult due to the large gene size and the prevalence of private mutations 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

2. Guay-Woodford LM, Desmond RA: Autosomal recessive polycystic kidney disease: the clinical experience in North America. Pediatrics 2003;111:1072-1080

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

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

5. Harris PC, Rossetti S: Molecular genetics of autosomal recessive polycystic kidney disease. Mol Genet Metab 2004;81:75-85

Day(s) and Time(s) Performed

Performed weekly; Varies

Analytic Time

14 days

Test 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 U.S. 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 48968-2

 

Result ID Test Result Name Result LOINC Value
53449 Result Summary 50397-9
53450 Result In Process
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

Mayo Clinic Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

mml-inherited-molecular