Multiple Pterygium Syndrome via the CHRNG 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
11177 CHRNG 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11177CHRNG81479 81479(x2) $890 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. If the Sanger option is selected, CNV detection may be ordered through Test #600.

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).

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

For Sanger Sequencing click here.

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

Like fetal akinesia deformation sequence, multiple pterygium syndrome may be caused by impaired intrauterine movement secondary to abnormalities in proteins at the neuromuscular junction. Lethal multiple pterygium syndrome (LMPS, OMIM 253290) is characterized by prenatal growth deficiency, contractures, pterygia, and dysmorphic facies. Joint contractures and multiple pterygia are universal findings. Patients are stillborn or do not survive beyond the newborn period. Pulmonary hypoplasia is likely the primary cause of mortality. Contractures are found at the elbows, knees, hips, shoulders, hands, and feet. Pterygia are found between the chin and sternum as well as the popliteal, axillary, antecubital, and ankle areas. Facial features include ocular hypertelorism, epicanthal folds, small chin and mouth, and low-set ears. Patients commonly are born with hydrops and pregnancies are affected with polyhydramnios. Escobar syndrome or Escobar variant of multiple pterygium syndrome (OMIM 265000) has clinical features that are similar to but milder than LMPS. Patients have normal intelligence and most are able to walk. Pterygia occur at the neck, axillae, popliteal, antecubital, and intercrural areas. Facial features include ptosis, hypertelorism, small chin and mouth, long philtrum, and low-set ears. Patients may have difficulty opening their mouths widely and exhibit an emotionless facial appearance. Other findings include camptodactyly, syndactyly, club feet, and hypoplastic genitalia. Respiratory complications resulting from scoliosis and kyphosis may occur.

Genetics

Abnormalities of proteins involved with neuromuscular transmission underlie multiple pterygium syndromes, congenital myasthenia syndromes, limb girdle myasthenia syndrome, and Pena-Shokeir syndrome. These disorders, which may represent a phenotypic continuum of a single entity, are most often inherited in an autosomal recessive manner. Variants in CHRNG cause both LMPS and Escobar syndrome (Hoffman et al. Am J Hum Genet 79:303-312, 2006; Morgan et al. Am J Hum Genet 79:390-395, 2006). CHRNA1 and CHRND variants also underlie LMPS (Michalk et al. Am J Hum Genet 82:464-476, 2008). CHRNG encodes the gamma subunit of the acetylcholine receptor which is expressed only during fetal development. The mature acetylcholine receptor contains the epsilon subunit in place of the gamma subunit.

Clinical Sensitivity - Sequencing with CNV PGxome

Analytical sensitivity should be high because the variants reported are readily detectable by gene sequencing. Clinical sensitivity may be low because fetal akinesia has multiple underlying causes including environmental, immunological, and genetic.

Testing Strategy

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

Stillborn patients with features of LMPS or patients with features of Escobar syndrome. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in CHRNG.

Gene

Official Gene Symbol OMIM ID
CHRNG 100730
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Diseases

Name Inheritance OMIM ID
Escobar Syndrome AR 265000
Lethal Multiple Pterygium Syndrome AR 253290

Citations

  • Hoffmann, K., et.al. (2006). "Escobar syndrome is a prenatal myasthenia caused by disruption of the acetylcholine receptor fetal gamma subunit." Am J Hum Genet 79(2): 303-12. PubMed ID: 16826520
  • Michalk, A., et.al. (2008). "Acetylcholine receptor pathway mutations explain various fetal akinesia deformation sequence disorders." Am J Hum Genet 82(2): 464-76. PubMed ID: 18252226
  • Morgan, N. V., et.al. (2006). "Mutations in the embryonal subunit of the acetylcholine receptor (CHRNG) cause lethal and Escobar variants of multiple pterygium syndrome." Am J Hum Genet 79(2): 390-5. PubMed ID: 16826531

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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