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Surfactant Protein B Deficiency via the SFTPB 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
11663 SFTPB 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11663SFTPB81479 81479,81479 $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

  • Fang Xu, PhD, FACMG

Clinical Features and Genetics

Clinical Features

Surfactant Protein B (SP-B) deficiency is a severe respiratory disorder due to dysfunction of surfactant composition. Surfactant is a lipid and protein mixture lining the lung tissue that lowers alveolar surface tension and prevents atelectasis during expiration. Loss of surfactant function results in alveoli collapse following expiration leading to shortness of breath and impaired oxygen delivery in the lung. In severe forms, respiratory failure occurs shortly after birth with infants requiring mechanical ventilation and lung transplantation for survival (Nogee et al. 2000; Tredano et al. 2003). SP-B deficiency patients fail to respond to surfactant replacement or corticosteroid therapy. Patients with milder forms of SP-B deficiency present with gradual hypoxemia, failure to thrive, and tachypnea (Ballard et al. 1995). Genetic testing is helpful in the differential diagnosis of SP-B deficiency from other surfactant deficiencies, respiratory infections, cardiac disorders with obstructed pulmonary venous return, and other respiratory distress syndromes (Hamvas 2006).

Genetics

SF-B deficiency is inherited in an autosomal recessive manner through pathogenic variants in the SFTPB gene. Surfactant dysfunction may also be inherited in an autosomal dominant manner through pathogenic variants in the SFTPC and NKX2.1 genes or an autosomal recessive manner through pathogenic variants in the ABCA3 gene (Hamvas 2006). In the SFTPB gene, the c.397delCinsGAA (p.Pro133Glufs*95), commonly referred to as 121ins2, is the most frequently observed pathogenic variant and accounts for over half of cases to date (Nogee et al. 2000). The majority of pathogenic variants lead to complete loss of SFTPB function and include splice site, nonsense, insertion/deletions resulting in a frameshift, and missense changes causing a loss of protein stability (Hamvas 2006; Nogee et al. 2000; Tredano et al. 2003). In rare occasions, partial SF-B deficiency has been seen in individuals with missense variants and results in a milder form of disease (Ballard et al. 1995). Pathogenic variants have been reported throughout the coding region of the SFTPB gene. Multi-exonic deletions have been reported in two cases (Wegner et al. 2007; Schuerman et al. 2008). The SFTPB gene encodes surfactant protein B which is a hydrophobic protein that enhances surface tension to prevent collapse of airways following expiration (Hamvas 2006).

Clinical Sensitivity - Sequencing with CNV PGxome

In a series of 32 affected infants with a diagnosis of SP-B, pathogenic variants in the SFTPB gene were identified in all cases. Sixteen were homozygous for c.391delCinsGAA, 10 compound heterozygous with c.391delCinsGAA and a second pathogenic variant, and 6 homozygous for other pathogenic variants (Nogee et al. 2000). Analytical sensitivity is >95% for detection of causative variants in the SFTPB gene by sequencing. Multi-exonic deletions have been found in two cases (Wegner et al. 2007; Schuerman et al. 2008).

Testing Strategy

This test provides full coverage of all coding exons of the SFTPB 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 testing present with neonatal respiratory failure. High resolution computerized tomography revealing ground-glass opacities of alveoli and thickening of interlobular and intralobular septa are indicative of interstitial lung disease due to loss of surfactant function. Lung biopsy showing accumulation of macrophages and desquamative interstitial pneumonitis are common histologic features for SP-B (Hamvas 2006). This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in SFTPB.

Gene

Official Gene Symbol OMIM ID
SFTPB 178640
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Surfactant Metabolism Dysfunction, Pulmonary, 1 AR 265120

Citations

  • Ballard PL. et al. 1995. Pediatrics. 96: 1046-52. PubMed ID: 7491219
  • Hamvas A. 2006. Seminars in Perinatology. 30: 316-26. PubMed ID: 17142157
  • Nogee LM. et al. 2000. American Journal of Respiratory and Critical Care Medicine. 161: 973-81. PubMed ID: 10712351
  • Schuerman FA. et al. 2008. European Journal of Medical Research. 13: 281-6. PubMed ID: 18558554
  • Tredano M. et al. 2003. American Journal of Medical Genetics. Part A. 119A: 324-39. PubMed ID: 12784301
  • Wegner DJ. et al. 2007. Acta Paediatrica (oslo, Norway : 1992). 96: 516-20. PubMed ID: 17391469

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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