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Test ID RFSGS Focal Segmental Glomerulosclerosis (FSGS) and Nephrotic Syndrome Gene Panel, Varies


Ordering Guidance


Targeted testing for familial variants (also called site-specific or known mutations testing) is available for the genes on this panel. See FMTT / Familial Mutation, Targeted Testing, Varies. To obtain more information about this testing option, call 800-533-1710.

 

Customization of this panel and single gene analysis for any gene present on this panel are available. For more information, see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies.



Shipping Instructions


Specimen preferred to arrive within 96 hours of collection.



Specimen Required


Specimen Type: Whole blood

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.

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 whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient (preferred)/Refrigerated


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:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing (Spanish) (T826)

2. Hereditary Renal Genetic Testing Patient Information (T918)

Useful For

Providing a genetic evaluation for patients with a personal or family history of steroid resistant nephrotic syndrome (SRNS)

 

Establishing a diagnosis of hereditary SRNS

 

Guiding treatment decisions in individuals with nephrotic syndrome

Method Name

Sequence Capture and Amplicon-Based Next-Generation Sequencing (NGS)

Reporting Name

FSGS/Nephrotic Syndrome Gene Panel

Specimen Type

Varies

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Clinical Information

Nephrotic syndrome (NS) is a kidney disorder characterized by proteinuria, hypoalbuminemia, and edema. Many conditions can cause NS, including diseases that only affect the kidney and other more systemic disorders such as diabetes or lupus. Focal segmental glomerulosclerosis (FSGS), a histologic finding characterized by sclerosis involving part of the kidney glomeruli, is commonly found in patients with NS.(1)

 

Approximately 85% of nephrotic syndrome is steroid sensitive, while the remaining 15% is steroid resistant (SRNS). SRNS may be genetic or nongenetic. Nongenetic causes of NS/FSGS may be due to a circulating factor causing generalized injury to podocytes, structural renal abnormalities, viral or drug-induced causes, or other stress on the kidney such as obesity, congenital heart disease, malignancy, or hypertension.(2)

 

Genetic SRNS may result from disease-causing variants in genes encoding renal-specific proteins (renal-limited) or syndromic conditions with extrarenal features.(2) Autosomal recessive forms of nonsyndromic SRNS typically present in childhood and are caused by disease-causing variants in nephrin (NPHS1), podocin (NPHS2), CD2AP, PLCE1, MYO1E, and multiple other genes. Autosomal dominant SRNS is typically adult onset and may be caused by disease-causing variants in TRPC6, ACTN4, INF2, and other genes. Variants in type IV collagen genes, known to cause Alport syndrome, may also be identified in patients with familial or sporadic SNRS and present later in adolescence or adulthood.

 

In syndromic forms of SRNS, extrarenal manifestations may be prominent and diagnostic, but in some cases, extrarenal features may be subtle or develop later in the disease course, such as in Denys-Drash syndrome (DDS) and Frasier syndrome caused by disease-causing variants in WT1.

 

Other genes included on this panel cover a broad spectrum of conditions that may display proteinuria, NS, or FSGS, either as an isolated feature or as part of a more systemic presentation, including genes associated with congenital disorders of glycosylation, Alport syndrome, coenzyme Q10 deficiency, and others.

 

This test also includes assessment of the G1 and G2 alleles of the APOL1 gene. The G1 and G2 alleles have been associated with increased risk for development or progression of nondiabetic chronic kidney diseases, including nonsyndromic SRNS.(3)

 

Despite some clinical and histologic overlap among the various categories of NS, management and prognosis may differ based on the underlying etiology. In particular, steroid sensitive NS may respond to treatment with corticosteroids, while SRNS, including those due to genetic causes, typically does not.(2) Therefore, identification of a genetic form of SRNS may impact evaluation for extra-renal manifestations, treatment decisions including transplantation, and genetic counselling.(4)

Reference Values

An interpretive report will be provided.

Interpretation

All detected variants are evaluated according to American College of Medical Genetics and Genomics recommendations.(5) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.

Clinical Reference

1. Chen YM, Liapis H: Focal segmental glomerulosclerosis: molecular genetics and targeted therapies. BMC Nephrol. 2015 Jul 9;16:101

2. De Vriese AS, Sethi S, Nath KA, et al: Differentiating primary, genetic, and secondary FSGS in adults: A clinicopathologic approach. J Am Soc Nephrol. 2018 Mar;29(3):759-774

3. Parsa A, Kao WH, Xie D, et al: APOL1 risk variants, race, and progression of chronic kidney disease. N Engl J Med. 2013;369(23):2183-2196. doi: 10.1056/NEJMoa13103454

4. Rood IM, Deegens JKJ, Wetzels JFM: Genetic causes of focal segmental glomerulosclerosis: implications for clinical practice. Nephrol Dial Transplant. 2012 Mar;27(3):882-890

5. 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

Day(s) Performed

Varies

Report Available

28 to 42 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 US Food and Drug Administration.

CPT Code Information

81408 x 2

81405 x 2

81406 x 4

81407 x 4

81479

81479 (if appropriate for government payers)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
RFSGS FSGS/Nephrotic Syndrome Gene Panel 51966-0

 

Result ID Test Result Name Result LOINC Value
618115 Test Description 62364-5
618116 Specimen 31208-2
618117 Source 31208-2
618118 Result Summary 50397-9
618119 Result 82939-0
618120 Interpretation 69047-9
618121 Additional Results In Process
618122 Resources 99622-3
618123 Additional Information 48767-8
618124 Method 85069-3
618125 Genes Analyzed 48018-6
618126 Disclaimer 62364-5
618127 Released By 18771-6