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Infantile Liver Failure Syndrome Panel

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy Genes Gene CPT Codes Copy CPT Codes
LARS1 81479,81479
NBAS 81479,81479
Test Code Test Copy Genes Panel CPT Code Gene CPT Codes Copy CPT Code Base Price
10089Genes x (2)81479 81479(x4) $990 Order Options and Pricing

Pricing Comments

We are happy to accommodate requests for testing single genes in this panel or a subset of these genes. The price will remain the list price. If desired, free reflex testing to remaining genes on panel is available. Alternatively, a single gene or subset of genes can also be ordered via our Custom Panel tool.

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 platform).

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

Turnaround Time

3 weeks on average for standard orders or 2 weeks 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.


Genetic Counselors


  • Ben Dorshorst, PhD

Clinical Features and Genetics

Clinical Features

Infantile liver failure syndrome is a life-threatening condition characterized by recurrent episodes of acute liver failure in infancy or early childhood. Recurrent acute liver failure (RALF) triggered by febrile infections can be caused by biallelic pathogenic variants in the NBAS gene (Haack et al. 2015. PubMed ID: 26073778). Liver function can be recovered completely with conservative management during the interval between infections. NBAS deficiency can lead to isolated RALF only or a multisystemic disorder with short stature, skeletal dysplasia, immunological abnormalities, and optic atrophy (resembling SOPH syndrome - short stature, optic nerve atrophy, and Pelger-Huet anomaly) (Staufner et al. 2016. PubMed ID: 26541327).

In addition, infantile liver failure syndrome has also been reported to be caused by defects in the LARS1/LARS gene. The phenotypic spectrum of LARS deficiency includes acute liver failure in infancy, anemia, renal tubulopathy, abnormal brain MRIs, failure to thrive, developmental delay, and seizures (Casey et al. 2012. PubMed ID: 22607940).


Infantile liver failure syndrome is an autosomal recessive disorder caused by defects in the NBAS gene or, much less frequently, in the LARS1 gene (Haack et al. 2015. PubMed ID: 26073778; Staufner et al. 2016. PubMed ID: 26541327; Casey et al. 2012. PubMed ID: 22607940).

The protein encoded by the NBAS gene (52 coding exons) is considered a component of a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. It is suggested to interact with partner p31, both involved in retrograde transport between endoplasmic reticulum (ER) and Golgi. Genetic defects within the NBAS gene include missense and various truncating variants (nonsense, splicing, and frameshift) (Human Gene Mutation Database). Gross deletions have been also reported (Human Gene Mutation Database). Notably, most patients with hepatic phenotype have pathogenic variants within or before the sec39 domain of NBAS (amino acids 725–1376) (Staufner et al. 2016. PubMed ID: 26541327).

The LARS1 gene (32 coding exons) encodes a cytoplasmic leucyl-tRNA synthetase enzyme, which catalyzes the ATP-dependent ligation of L-leucine to tRNA(Leu) during protein translation. So far, only missense variants in this gene have been reported in patients with infantile liver failure syndrome (Human Gene Mutation Database).

Clinical Sensitivity - Sequencing with CNV PGxome

Sequencing of the NBAS gene in 15 unrelated individuals with recurrent acute liver failure (RALF) or acute liver failure (ALF) revealed biallelic pathogenic variants in five families (33%) (Haack et al. 2015. PubMed ID: 26073778).

The pathogenic variant detection rate in the LARS1 gene in a large cohort of patients is unavailable because documented cases in the literature are limited (Casey et al. 2012. PubMed ID: 22607940).

Testing Strategy

This test is performed using Next-Gen sequencing with additional Sanger sequencing as necessary.

This panel provides 100% coverage of all coding exons of the genes 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 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 are patients with acute infantile liver failure, especially if triggered by fever.


Official Gene Symbol OMIM ID
LARS1 151350
NBAS 608025
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Related Test



  • Casey et al. 2012. PubMed ID: 22607940
  • Haack et al. 2015. PubMed ID: 26073778
  • Human Gene Mutation Database (Bio-base).
  • Staufner et al. 2016. PubMed ID: 26541327


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

If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.

Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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View Ordering Instructions

1) Select Test Method (Platform)

1) Select Test Type

2) Select Additional Test Options

No Additional Test Options are available for this test.

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