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Cortical Dysplasia, Complex, with Other Brain Malformations 4 via the TUBG1 Gene

Summary and Pricing

Test Method

Bi-Directional Sanger Sequencing
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
5898 TUBG1 81479 81479 $750 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
5898TUBG181479 81479 $750 Order Options and Pricing

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

Turnaround Time

12 days on average for standard orders or 8 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

  • Li Fan, MD, PhD, FCCMG, FACMG

Clinical Features and Genetics

Clinical Features

Cortical dysplasia, complex, with other brain malformations 4 is one type of heterogeneous tubulinopathy and is characterized by posterior predominant pachygyria. The major features include severe microcephaly, severe motor and cognitive impairment, and early onset seizures with generalized tonic-clonic, tonic–atonic–myoclonic, focal, versive and infantile spasms. Cataract and spastic tetraplegia also can be seen in some patients. Brain MRI shows pachygyric cortex with posterior to anterior gradient, enlarged lateral ventricles most pronounced over the posterior horns, and variable degrees of reduced white matter volume (Brock et al. 2018. PubMed ID: 29706637; Poirier et al. 2013. PubMed ID: 23603762). Seizure types are variable and include generalized tonic-clonic, atonic, myoclonic, complex partial, and absence.

Genetics

Cortical dysplasia, complex, with other brain malformations 4 is inherited in an autosomal dominant manner and is caused by pathogenic variants in the TUBG1 gene. TUBG1 encodes gamma-tubulin which is a structural protein of the centrosome and highly expressed in fetal brain. The TUBG1 protein associates with other proteins to form the gamma tubulin ring complex which plays a role in microtubule nucleation. The tubulin-related cortical dysgeneses are considered to involve a combination of abnormal neuronal proliferation, migration, differentiation and axonal guidance (Poirier et al. 2013. PubMed ID: 23603762). The reported pathogenic variants in TUBG1 include missense variants only at this time. Large deletions or duplications have not been reported (Brock et al. 2018. PubMed ID: 29706637; Poirier et al. 2013. PubMed ID: 23603762; Human Gene Mutation Database). Almost all of the pathogenic variants have occurred de novo. Germline mosaicism has been seen in one patient (Brock et al. 2018. PubMed ID: 29706637).

Clinical Sensitivity - Sanger Sequencing

Tubulinopathies are clinically and genetically heterogeneous. Clinical sensitivity for TUBG1 cannot be estimated because only a small number of patients have been reported. Analytical sensitivity should be high because all pathogenic variants reported are detectable by sequencing.

Testing Strategy

Our DNA sequencing test involves bidirectional Sanger DNA sequencing of all coding exons of the TUBG1 gene plus ~10 bp of flanking non-coding DNA on either side of each exon. We will also sequence any single exon (Test #100) in family members of patients with a known pathogenic variant or to confirm research results.

Indications for Test

The TUBG1 sequencing test is recommended for patients who are suspected to have cortical dysplasia, complex, with other brain malformations 4.

Gene

Official Gene Symbol OMIM ID
TUBG1 191135
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Citations

  • Brock et al. 2018. PubMed ID: 29706637
  • Human Gene Mutation Database (Bio-base).
  • Poirier et al. 2013. PubMed ID: 23603762

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

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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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