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Spastic Paraplegia 8 via the WASHC5/KIAA0196 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
WASHC5 81407 81407,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8013WASHC581407 81407,81479 $990 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.

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).

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

For Sanger Sequencing click here.

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 8 (SPG8) is a type of hereditary spastic paraplegia (HSP) and is characterized by slowly progressive spasticity and weakness of lower limbs (Valdmanis et al. 2008). It is a “pure” form of HSP, i.e., the symptoms are limited to lower limbs. Some affected individuals may demonstrate decreased vibration sense and urinary urgency (Depienne et al. 2007). Interfamilial and intrafamilial phenotypic variation is common. On average, the age of onset is in 20s and 30s (Valdmanis et al. 2008). Generally, SPG8 is a severe type of HSP compared to many other types, and most patients with SPG8 become wheelchair bound by age 40 years (Hedera et al. 1999; Reid et al. 1999).

SPG8 is indistinguishable clinically from many others forms of HSP, such as SPG3A, SPG4, SPG6, SPG10, SPG12, SPG13 and SPG19. Therefore, molecular genetic testing is very useful in a precise diagnosis of this disease.


SPG8 is inherited in an autosomal dominant (AD) manner, and the penetrance is approximately 90%-100% (Valdmanis et al. 2008). SPG8 is caused by pathogenic variants in the WASHC5/KIAA0196 gene (Valdmanis et al. 2007), which is the only known causative gene for SPG8. WASHC5 encodes the protein strumpellin, a 1159-residue protein containing one spectrin repeat and a domain of unknown significance with high level of conservation (Valdmanis et al. 2007). To date, ten missense variants and one gross deletion have been identified in WASHC5 to cause SPG8 (Human Gene Mutation Database; Ichinose et al. 2016). Of note, it seems that all the known pathogenic variants for SPG8 cluster in the central part of the strumpellin protein. The strumpellin protein also physically binds VCP (valosin-containing protein), which is also involved in spastic paraplegia (de Bot et al. 2012)

Elliott et al. identified a homozygous splice site variant in the WASHC5 gene, which is causative for a developmental malformation syndrome, Ritscher-Schinzel Syndrome 1 (RTSC1) (Elliott et al. 2013).

Clinical Sensitivity - Sequencing with CNV PGxome

WASHC5 pathogenic variants have been reported in a few SPG8 families; however, it is difficult to estimate the clinical sensitivity of this test due to the lack of large cohort studies.

Testing Strategy

This test provides full coverage of all coding exons of the WASHC5 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

Individuals with symptoms consistent with autosomal dominant HSP, and family members of patients who have known WASHC5-HSP mutations are candidates for this test.


Official Gene Symbol OMIM ID
WASHC5 610657
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Spastic Paraplegia 8 AD 603563


  • de Bot S.T. et al. 2012. Brain. 135: e223; author reply e224. PubMed ID: 22991237
  • Depienne C. et al. 2007. Current Opinion in Neurology. 20: 674-80. PubMed ID: 17992088
  • Elliott A.M. et al. 2013. Journal of Medical Genetics. 50: 819-22. PubMed ID: 24065355
  • Hedera P. et al. 1999. American Journal of Human Genetics. 64: 563-9. PubMed ID: 9973294
  • Human Gene Mutation Database (Bio-base).
  • Ichinose Y. et al. 2016. Clinical Neurology and Neurosurgery. 144: 36-8. PubMed ID: 26967522
  • Reid E. et al. 1999. Neurology. 53: 1844-9. PubMed ID: 10563637
  • Valdmanis et al. 2008. Spastic Paraplegia 8. In: Pagon RA, Adam MP, Bird TD, Dolan CR, Fong C-T, Smith RJ, and Stephens K, editors. GeneReviews™, Seattle (WA): University of Washington, Seattle. PubMed ID: 20301727
  • Valdmanis P.N. et al. 2007. American Journal of Human Genetics. 80: 152-61. PubMed ID: 17160902


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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