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Spastic Paraplegia 18 via the ERLIN2 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
ERLIN2 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
4903ERLIN281479 81479,81479 $990 Order Options and Pricing

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


  • Greg Fischer, PhD

Clinical Features and Genetics

Clinical Features

Spastic Paraplegia 18 (SPG18) is a type of complex hereditary spastic paraplegia (HSP) with severe symptoms. Patients with SPG18 usually show early onset (before the age of 1 or 2 years) of features suggestive of spasticity, including ankle clonus, extensor plantar response, and hyperactive reflexes. Symptoms begin in the feet and spread in an ascending manner, and eventually affect the spine and neck. SPG18 patients typically have delayed motor development and intellectual disability, and are not able to speak, read or write. A few patients may also show seizures and epilepsy (Alazami et al. 2011; Yildirim et al. 2011). Some SPG18 patients may become wheelchair-bound in childhood (Alazami et al. 2011).


SPG18 is inherited as an autosomal recessive (AR) disorder. In a consanguineous Saudi family with SPG18, Alazami et al. (2011) identified a homozygous ~20 kb deletion that disrupts the coding region of ERLIN2 gene. Other studies identified a frameshift pathogenic variant (Yildirim et al. 2011) and a splicing pathogenic variant (Wakil et al. 2013), and confirmed that ERLIN2 loss of function could cause the SPG18 phenotype. ERLIN2 and its paralog ERLIN1 (SPG62) regulate the endoplasmic reticulum-associated degradation (ERAD) of inositol 1,4,5-trisphosphate receptors (IP3Rs). The mechanism of ERLIN2-associated SPG18 is not clear, however, it has been postulated that loss function of ERLIN2 may lead to persistent activation of IP3 signaling and neuronal channel activity (Alazami et al. 2011).

Clinical Sensitivity - Sequencing with CNV PGxome

It is difficult to estimate the clinical sensitivity of this test due to the lack of large cohort studies. All the reported pathogenic variants in ERLIN2 are detectable by sequencing.

Testing Strategy

This test provides full coverage of all coding exons of the ERLIN2 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

Patients with clinical symptoms consistent with the complex form of autosomal recessive HSP may consider this test. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in ERLIN2.


Official Gene Symbol OMIM ID
ERLIN2 611605
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Spastic Paraplegia 18 AR 611225


  • Alazami .A.M et al. 2011. Neurogenetics. 12: 333-6. PubMed ID: 21796390
  • Wakil S.M. et al. 2013. European Journal of Medical Genetics. 56: 43-5. PubMed ID: 23085305
  • Yildirim Y. et al. 2011. Human Molecular Genetics. 20: 1886-92. PubMed ID: 21330303


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)

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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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