Nemaline Myopathy 9 via the KLHL41 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
11435 KLHL41 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11435KLHL4181479 81479 $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.

A 25% additional charge will be applied to STAT orders. View STAT turnaround times here.

For Reflex to PGxome pricing click here.

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

For Sanger Sequencing click here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.

Turnaround Time

18 days on average

EMAIL CONTACTS

Genetic Counselors

Geneticist

Clinical Features and Genetics

Clinical Features

Nemaline myopathy (NM) is a genetically and clinically heterogeneous disorder characterized by muscle weakness, hypotonia and the presence of nemaline bodies in skeletal muscle fibers. Muscle weakness is typically observed in affected neonates or infants, although later onset cases have been reported (Ryan et al. 2001). The most severely affected muscle groups are proximal limb, facial, bulbar, and respiratory muscles. Deep tendon reflexes are absent or depressed. Histologically, NM is characterized by type 1 fiber predominance and the presence of rod-like structures called nemaline bodies upon Gomori trichrome staining of skeletal muscle (Ryan et al. 2003). Six clinical types of NM have been delineated based on age of onset, severity and distribution of weakness, and respiratory function (Ryan et al. 2001; North and Ryan. 2002). Overlap among the six clinical groups is significant and adults are sometimes diagnosed only after another family member has presented with typical signs. Nemaline myopathy 9 is caused by pathogenic variants in the KLHL41 gene. A severe phenotype with fetal hyopkenisia and neonatal death is associated with KLHL41 frameshift variants, whereas missense variants lead to mild presentation with survival into late childhood or early adulthood (Gupta et al. 2013).

Genetics

KLHL41-related nemaline myopathy (NEM9) is an autosomal recessive disorder. KLHL41 encodes a Kelch-like family member protein. Defects in KLHL41 lead to impaired motor function and myofibrillar disorganization (Gupta et al. 2013). The types of mutations reported include missense, small deletions/insertions, and one gross deletion (Gupta et al. 2013).

Clinical Sensitivity - Sequencing with CNV PGxome

Clinical sensitivity is expected to be low. Four patients affected with Nemaline Myopathy 9 were reported to date (Gupta et al. 2013).

Testing Strategy

This test provides full coverage of all coding exons of the KLHL41 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.

Since this test is performed using exome capture probes, a reflex to any of our exome based tests is available (PGxome, PGxome Custom Panels).

Indications for Test

Individuals with clinical symptoms consistent with nemaline myopathy and a muscle biopsy with nemaline bodies. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in KLHL41.

Gene

Official Gene Symbol OMIM ID
KLHL41 607701
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Nemaline Myopathy 9 AR 615731

Citations

  • Gupta VA, Ravenscroft G, Shaheen R, Todd EJ, Swanson LC, Shiina M, Ogata K, Hsu C, Clarke NF, Darras BT, Farrar MA, Hashem A, Manton ND, Muntoni F, North KN, Sandaradura SA, Nishino I, Hayashi YK, Sewry CA, Thompson EM, Yau KS, Brownstein CA, Yu TW, Allcock RJ, Davis MR, Wallgren-Pettersson C, Matsumoto N, Alkuraya FS, Laing NG, Beggs AH. 2013. Identification of KLHL41 Mutations Implicates BTB-Kelch-Mediated Ubiquitination as an Alternate Pathway to Myofibrillar Disruption in Nemaline Myopathy. Am. J. Hum. Genet. 93: 1108–1117. PubMed ID: 24268659
  • North K, Ryan MM. 2002. Nemaline Myopathy. In: Pagon RA, Adam MP, Bird TD, Dolan CR, Fong C-T, and Stephens K, editors. GeneReviews™, Seattle (WA): University of Washington, Seattle. PubMed ID: 20301465
  • Ryan MM, Ilkovski B, Strickland CD, Schnell C, Sanoudou D, Midgett C, Houston R, Muirhead D, Dennett X, Shield LK, Girolami U De, Iannaccone ST, Laing NG, North KN, Beggs AH. 2003. Clinical course correlates poorly with muscle pathology in nemaline myopathy. Neurology 60: 665–673. PubMed ID: 12601110
  • Ryan MM, Schnell C, Strickland CD, Shield LK, Morgan G, Iannaccone ST, Laing NG, Beggs AH, North KN. 2001. Nemaline myopathy: a clinical study of 143 cases. Ann. Neurol. 50: 312–320. PubMed ID: 11558787

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.

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

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ORDER OPTIONS

View Ordering Instructions

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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.

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