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Pierson Syndrome and Congenital Nephrotic Syndrome via the LAMB2 Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
11443 LAMB2 81407 81407,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11443LAMB281407 81407(x1), 81479(x1) $890 Order Options and Pricing

Pricing Comments

Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information. If the Sanger option is selected, CNV detection may be ordered through Test #600.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Click here for costs to reflex to whole PGxome (if original test is on PGxome Sequencing backbone).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing backbone).

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

Turnaround Time

18 days on average for standard orders or 13 days on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Angela Gruber, PhD

Clinical Features and Genetics

Clinical Features

Defects in the LAMB2 gene can cause congenital nephrotic syndrome with or without ocular abnormalities (Matejas et al. 2010). Nephrotic syndrome is a genetically heterogeneous disease defined by proteinuria, hypoalbuminemia, hyperlipidemia, and edema (Benoit et al. 2010; Santín et al. 2011; Saleem 2012). Approximately 20% of cases are steroid-resistant nephrotic syndrome (SRNS), characterized by resistance to steroid treatment and rapid progression to end-stage renal failure. The prevalent histological feature of SRNS is focal segmental glomerulosclerosis (FSGS), which has been seen in approximately 60% of SRNS cases. Diffuse mesangial sclerosis (DMS) is the other important histological feature associated with SRNS. The clinical courses of SRNS vary greatly with a wide range of age at onset from birth to adulthood.

When distinct ocular abnormalities (featured by microcoria and hypoplasia of the ciliary and pupillary muscles) present alongside congenital nephrotic syndrome with diffuse mesangial sclerosis (DMS) histologically, Pierson syndrome due to a complete loss of LAMB2 expression resulted from null alleles should be suspected (Zenker et al. 2004). Severe neurodevelopmental abnormalities including congenital muscular weakness/myasthenia and developmental retardation are also commonly seen in Pierson syndrome.

Different from those with Pierson syndrome, patients with compound heterozygous or homozygous missense variants in the LAMB2 gene generally only develop congenital nephrotic syndrome with minor ocular abnormalities or isolated congenital nephrotic syndrome (Hasselbacher et al. 2006).

Genetics

The LAMB2 gene (32 coding exons) encodes the basement membrane protein laminin beta2. Both Pierson syndrome and LAMB2-related congenital nephrotic syndrome are autosomal recessive disorders due to LAMB2 defects, caused by null alleles and missense variants, respectively (Zenker et al. 2004; Hasselbacher et al. 2006; Matejas et al. 2010). Notably, genetic modifiers have been suspected to exist to explain some genotype-phenotype discordance (Matejas et al. 2010). To date, documented genetic defects of LAMB2 include missense, nonsense, splicing, regulatory mutations, and small indels (Human Gene Mutation Database). Large deletions and duplications have not been reported.

Clinical Sensitivity - Sequencing with CNV PGxome

LAMB2 defects are a rare cause of isolated congenital nephrotic syndrome. In a large European cohort of 89 children from 80 families with nephrotic syndrome manifesting in the first year of life, LAMB2 pathogenic variants were found in only 2.5% of these families (Hinkes et al. 2007).

Mutation detection rate of the LAMB2 gene in a large cohort of patients with Pierson syndrome is unavailable in the literature because pathogenic variants in this gene have only been reported in limited cases from individual studies.

Testing Strategy

This test provides full coverage of all coding exons of the LAMB2 gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).

Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).

Indications for Test

Candidates for this test can be patients with Pierson syndrome or congenital nephrotic syndrome. Testing is also indicated for family members of patients who have known mutations in the LAMB2 gene. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in LAMB2.

Gene

Official Gene Symbol OMIM ID
LAMB2 150325
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Citations

  • Benoit G. et al. 2010. Pediatric Nephrology (berlin, Germany). 25: 1621-32. PubMed ID: 20333530
  • Hasselbacher K. et al. 2006. Kidney International. 70: 1008-12. PubMed ID: 16912710
  • Hinkes B.G. et al. 2007. Pediatrics. 119: e907-19. PubMed ID: 17371932
  • Human Gene Mutation Database (Bio-base).
  • Matejas V. et al. 2010. Human Mutation. 31: 992-1002. PubMed ID: 20556798
  • Saleem M.A. 2013. Pediatric Nephrology (berlin, Germany). 28: 699-709. PubMed ID: 22782578
  • Santín S. et al. 2011. Clinical Journal of the American Society of Nephrology : Cjasn. 6: 1139-48. PubMed ID: 21415313
  • Zenker M. et al. 2004. Human Molecular Genetics. 13: 2625-32. PubMed ID: 15367484

Ordering/Specimens

Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page


Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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ORDER OPTIONS

View Ordering Instructions

1) Select Test Method (Backbone)


1) Select Test Type


2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
Total Price: $
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