Charcot-Marie-Tooth Type 4C via the SH3TC2 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
11665 SH3TC2 81406 81406,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11665SH3TC281406 81406(x1), 81479(x1) $890 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 backbone).

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

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

  • Angela Gruber, PhD

Clinical Features and Genetics

Clinical Features

Charcot Marie Tooth disease (CMT), also known as hereditary motor and sensory neuropathy (HMSN), is a large group of inherited disorders of the peripheral nerves. The progressive degeneration of motor nerves results in weakness and atrophy of the distal muscles; and the degeneration of sensory nerves leads to decreased sensation, tingling and numbness in the legs, feet, arms and hands and neuropathic pain. The age of onset varies from childhood to mid adulthood. Symptoms usually begin with weakness and atrophy in the muscle of the legs and feet. As the disease progresses, weakness and atrophy of the muscles of the arms and hands may occur. CMT is heterogeneous in regards to symptoms, severity and progression rate. Although the disease may lead to disability and respiratory difficulty, life expectancy is usually unaffected. Most common symptoms include foot deformity, loss of balance, hammertoes, foot drop, frequent tripping and falls, and reduced manual dexterity. Diagnosis is based on clinical features, family history, neurological examination, electromyography (EMG), nerve conduction velocity (NCV), and genetic testing (Pareyson and Marchesi, 2009. PubMed ID: 19539237; Bird, 2015. PubMed ID: 20301532). CMT affects approximately 1 in 3,300 people.

Charcot-Marie-Tooth type 4C (CMT4C) is caused by pathogenic variants in SH3TC2 and was first reported by Senderek et al., 2003 (PubMed ID: 14574644). CMT4C is a demyelinating neuropathy that many times is early onset with severe spine deformities. Children typically present between the ages of 2-10 with scoliosis or kyphoscoliosis, although variable onset has been observed. Foot deformities are also commonly observed between the ages of 2-10. A slowly progressive neuropathy is observed in the first decade or during adolescence. For a full review of CMT4C, see Azzedine et al., 2015 (PubMed ID: 20301514).

Genetics

Charcot-Marie-Tooth type 4C (CMT4C) is inherited in an autosomal recessive manner due to pathogenic variants in SH3TC2, located on chromosome 5q32. The SH3TC2 gene encodes SH3 domain and tetratricopeptide repeat-containing protein 2. The SH3TC2 protein is expressed in Schwann cells and is necessary for proper myelination of peripheral axons. Thus far, reported pathogenic variants include missense, nonsense, splicing, and small deletions/duplications which result in a frameshift and premature protein termination (Human Gene Mutation Database).

Clinical Sensitivity - Sequencing with CNV PGxome

Overall, Charcot-Marie-Tooth 4 (CMT4C) is a rare category of CMT (Bird 2015). On the basis of the cumulative data, the prevalence of CMT4C among those with CMT4 is approximately 18% (53/299) (Azzedine et al., 2015). Analytical sensitivity should be high because all reported pathogenic variants thus far are detectable by sequencing.

Thus far, no large deletions or duplications involving the SH3TC2 gene have been reported (Human Gene Mutation Database).

Testing Strategy

This test provides full coverage of all coding exons of the SH3TC2 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 clinical symptoms consistent with Charcot-Marie-Tooth and autosomal recessive inheritance. Testing is also indicated for family members of patients who have known SH3TC2 pathogenic variants. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in SH3TC2.

Gene

Official Gene Symbol OMIM ID
SH3TC2 608206
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Charcot-Marie-Tooth Disease, Type 4C AR 601596

Citations

  • Azzedine et al., 2015. PubMed ID: 20301514
  • Bird, 2015. PubMed ID: 20301532
  • Human Gene Mutation Database (Bio-base).
  • Pareyson and Marchesi, 2009. PubMed ID: 19539237
  • Senderek et al., 2003. PubMed ID: 14574644

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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