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Distal Arthrogryposis Type 7 (Trismus-Pseudocamptodactyly Syndrome) via the MYH8 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
MYH8 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
9839MYH881479 81479,81479 $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.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Angela Gruber, PhD

Clinical Features and Genetics

Clinical Features

Distal arthrogryposis (DA) syndromes are a group of multiple congenital contracture disorders with distal joint involvement, variable clinical expression, and most often autosomal dominant inheritance (Bamshad et al. 2009).

Distal arthrogryposis type 7 (DA7), referred to as trismus-pseudocamptodactyly syndrome, is caused by pathogenic variants in MYH8. Trismus-pseudocamptodactyly syndrome (TPS) is a disorder of muscle development and function and is characterized by limited range of motion of the hands, legs, and mouth. TPS patients may not open the mouth fully (trismus) and show an unusual camptodactyly (flexion of the fingers) that is evident on dorsiflexion of the wrist (pseudocamptodactyly) (Ter Haar et al. 1974; Veugelers et al. 2004).

Genetics

Distal arthrogryposis type 7 is inherited in an autosomal dominant pattern. MYH8 encodes 1937 amino acids and spans over 32 kb on Chromosome 17p13.1 (Weiss et al. 1999). Muscle myosins consist of two heavy chains (MyHCs), two essential light chains (MLCs), and two regulatory MLCs. The neonatal myosin heavy chains, coded by the myosin heavy chain 8 gene (MYH8), are expressed during fetal development, disappear shortly after birth from most muscle, and only persist throughout adult stages in specialized muscles, such as the extraocular and jaw-closing muscles, and in the muscle spindles (Schiaffino et al. 2015). TPS has been reported to be caused by a single missense variant, c.2021G>A (p.Arg674Gln) in MYH8. The amino acid residue p.Arg674 of the MYH8 protein is an evolutionary conserved residue, localized in the actin-binding domain of the perinatal myosin head. This residue is also close to the ATP binding site and may thus interfere with ATP binding to the mutant myosin heavy chain (Veugelers et al. 2004; Toydemir et al. 2006).

Clinical Sensitivity - Sequencing with CNV PGxome

Clinical sensitivity cannot be estimated because only one missense pathogenic variant in MYH8 has been reported. Analytical sensitivity should be high because this missense variant is detectable by sequencing.

Testing Strategy

This test provides full coverage of all coding exons of the MYH8 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

All patients with symptoms suggestive of distal arthrogryposis are candidates for this test.

Gene

Official Gene Symbol OMIM ID
MYH8 160741
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Arthrogryposis, Distal, Type 7 AD 158300

Citations

  • Bamshad M. et al. 2009. The Journal of Bone and Joint Surgery. American Volume. 91 Suppl 4: 40-6. PubMed ID: 19571066
  • Human Gene Mutation Database (Bio-base).
  • Schiaffino S. et al. 2015. Skeletal Muscle. 5: 22. PubMed ID: 26180627
  • ter Haar B.G., van Hoof R.F. 1974. Journal of Medical Genetics. 11: 41-9. PubMed ID: 4837286
  • Toydemir R.M. et al. 2006. American Journal of Medical Genetics. Part A. 140: 2387-93. PubMed ID: 17041932
  • Veugelers M. et al. 2004. The New England Journal of Medicine. 351: 460-9. PubMed ID: 15282353
  • Weiss A. et al. 1999. Journal of molecular biology. 290:61-75. PubMed ID: 10388558

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

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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ORDER OPTIONS

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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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