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Congenital Muscular Dystrophy, Megaconial Type via the CHKB 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
CHKB 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11171CHKB81479 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. 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 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.


Genetic Counselors


  • Angela Gruber, PhD

Clinical Features and Genetics

Clinical Features

Congenital muscular dystrophy with mitochondrial structural abnormalities (MDCMC, OMIM 602541) is characterized by congenital-onset hypotonia, muscle wasting, mildly elevated serum CpK levels, mental retardation, and mitochondrial abnormalities. Muscle biopsies in these patients reveal dystrophic changes, fiber-size variation, increased endomysial connective tissue, and unusual distribution, size, and structure of mitochondria. Specifically, mitochondria are depleted in the center of the sarcoplasm, whereas the mitochondria at the periphery of muscle fibers are markedly enlarged and have abnormal cristae structure (Nishino et al. Muscle Nerve 21:40-47, 1998). Weakness is predominately proximal and slowly progressive and cardiomyopathy is often a cause of morbidity and mortality (Mitsuhashi et al. Am J Hum Genet 88:845-851, 2011). Among the first series of MDCMC patients described by Nishino et al. (1998), some individuals had delayed walking and others never achieved independent ambulation. Although most of the patients had microcephaly, none had structural brain abnormalities.


Congenital muscular dystrophy, megoconial type is inherited as an autosomal recessive disorder. The choline kinase beta enzyme, encoded by the CHKB gene (OMIM 612395), catalyzes the first step of phosphatidylcholine biosynthesis. Homozygous or compound heterozygous variants in the CHKB gene result in loss of choline kinase activity and decreased levels of phosphatidylcholine. Types of variants reported to date include nonsense, missense, splice site, and small deletions and duplications.

Clinical Sensitivity - Sequencing with CNV PGxome

Only a small number of patients have thus far been described with this form of congenital muscular dystrophy. However, clinical sensitivity may be high in patients meeting clinical and histological criteria for this disorder. Analytical sensitivity may also be high because all CHKB variants reported to date will be detectable by direct sequencing of genomic DNA.

Testing Strategy

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

Patients with congenital muscular dystrophy, mental retardation, absent or limited speech, and characteristic abnormalities of mitochondria distribution and structure. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in CHKB.


Official Gene Symbol OMIM ID
CHKB 612395
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Muscular Dystrophy, Congenital, Megaconial Type AR 602541


  • Mitsuhashi S, Ohkuma A, Talim B, Karahashi M, Koumura T, Aoyama C, Kurihara M, Quinlivan R, Sewry C, Mitsuhashi H, Goto K, Koksal B, et al. 2011. A Congenital Muscular Dystrophy with Mitochondrial Structural Abnormalities Caused by Defective De Novo Phosphatidylcholine Biosynthesis. The American Journal of Human Genetics 88: 845–851. PubMed ID: 21665002
  • Nishino I, Kobayashi O, Goto Y, Kurihara M, Kumagai K, Fujita T, Hashimoto K, Horai S, Nonaka I. 1998. A new congenital muscular dystrophy with mitochondrial structural abnormalities. Muscle Nerve 21: 40–47. PubMed ID: 9427222


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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View Ordering Instructions

1) Select Test Method (Platform)

1) Select Test Type

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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