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Spinal Muscular Atrophy with Respiratory Distress Type 1 via the IGHMBP2 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
IGHMBP2 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11387IGHMBP281479 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

Spinal muscular atrophy with respiratory distress type 1 (SMARD1; OMIM 604320) is a disease of the anterior horn cell that most often presents before 6 months of age with intrauterine growth retardation, foot deformities, distal muscle weakness, and respiratory failure due to diaphragmatic eventration and paralysis (Grohmann et al. Nat Genet 29:75-77, 2001). Muscle weakness is progressive and predominately affects the lower distal extremities. Motor nerve conduction velocities, particularly in the legs, are very slow (Pitt et al. Brain 126:2682-2692, 2003). Among a cohort of twenty-nine infants with variant-confirmed SMARD1, Grohmann et al. (2003) found that three-fourths of the patients had IUGR and more than a third were affected by prematurity. The most prominent feature was life-threatening respiratory distress, with stridor or a weak cry being the most common presenting signs. Nearly all patients developed eventration resulting in diaphragmatic paralysis. Muscle weakness was first evident in the lower distal muscles; however, upper limbs were subsequently affected, leading to paralysis of the trunk and limb muscles. Muscle biopsies showed neurogenic changes with myofiber hypertrophy and atrophy.


Spinal muscular atrophy with respiratory distress type 1 is inherited as an autosomal recessive disorder due to variants in the IGHMBP2 gene. IGHMBP2 encodes the immunoglobulin μ-binding protein 2, an ATP-dependent helicase which localizes to neuronal and non-neuronal cells and associates with ribosomes (Guenther et al. Hum Mol Genet 18:1288-1300, 2009). Degeneration of α-motor neurons from the anterior horn is likely related to disruption of protein translation (Guenther et al. 2009). Missense variants appear to be concentrated in the predicted helicase domains (Grohmann et al. Ann Neurol 54:719-724, 2003) while nonsense variants occur throughout the protein. Small deletions and splice site variants are also documented.

The immunoglobulin μ-binding protein l is coded by the IGHMBP2 gene (OMIM 600502) located on chr 11q13.

Clinical Sensitivity - Sequencing with CNV PGxome

Respiratory failure between ages 6 weeks and 6 months along with diaphragmatic eventration or, alternatively pre-term birth, is a highly sensitive predictor of IGHMBP2 involvement (Guenther et al. Hum Mutat 28:808- 815, 2007).

Testing Strategy

This test provides full coverage of all coding exons of the IGHMBP2 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

Infants with distal limb weakness and respiratory distress secondary to diaphragmatic paralysis. It is recommended that consanguineous parents of a child with sudden infant death syndrome consider carrier testing (Grohmann et al. Ann Neurol 54:719-724, 2003). This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in IGHMBP2.


Official Gene Symbol OMIM ID
IGHMBP2 600502
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Spinal Muscular Atrophy With Respiratory Distress 1 AR 604320


  • Grohmann, K., et.al. (2001). "Mutations in the gene encoding immunoglobulin mu-binding protein 2 cause spinal muscular atrophy with respiratory distress type 1." Nat Genet 29(1): 75-7. PubMed ID: 11528396
  • Grohmann, K., et.al. (2003). "Infantile spinal muscular atrophy with respiratory distress type 1 (SMARD1)." Ann Neurol 54(6): 719-24. PubMed ID: 14681881
  • Guenther, U. P., et.al. (2007). "Clinical and mutational profile in spinal muscular atrophy with respiratory distress (SMARD): defining novel phenotypes through hierarchical cluster analysis." Hum Mutat 28(8): 808-15. PubMed ID: 17431882
  • Guenther, U. P., et.al. (2009). "IGHMBP2 is a ribosome-associated helicase inactive in the neuromuscular disorder distal SMA type 1 (DSMA1)." Hum Mol Genet 18(7): 1288-300. PubMed ID: 19158098
  • Pitt, M., et.al. (2003). "Severe infantile neuropathy with diaphragmatic weakness and its relationship to SMARD1." Brain 126(Pt 12): 2682-92. PubMed ID: 14506069


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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2) Select Additional Test Options

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Note: acceptable specimen types are whole blood and DNA from whole blood only.
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