Distal Arthrogryposis Type 7 (Trismus-Pseudocamptodactyly Syndrome) via the MYH8 Gene
Summary and Pricing
Test Method
Exome Sequencing with CNV DetectionTest Code | Test Copy Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
---|---|---|---|---|---|
9839 | MYH8 | 81479 | 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.
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.
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
ORDER OPTIONS
View Ordering Instructions1) Select Test Type
2) Select Additional Test Options
No Additional Test Options are available for this test.