Hypertrophic Cardiomyopathy and Related Disorders via the TNNI3 Gene
Summary and Pricing 
Test Method
Exome Sequencing with CNV Detection
| Test Code | Test Copy Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
|---|---|---|---|---|---|
| 8657 | TNNI3 | 81405 | 81405,81479 | $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.
Clinical Features and Genetics
Clinical Features
Hypertrophic cardiomyopathy (HCM) is a primary disease of the cardiac muscle characterized by idiopathic hypertrophy of the left ventricle, although hypertrophy of the right ventricle may occur occasionally (Fifer and Vlahakes Circulation 117:429-439, 2008). HCM is distinguished by an extensive clinical variability between individuals with regards to the age of onset, pattern and extent of hypertrophy, and prognosis. Symptoms include dyspnea, exercise intolerance, chest pain, palpitations, arrhythmia, atrial fibrillation, syncope, and sudden death (Maron et al. N Engl J Med 316:780-789, 1987). Additional features include left ventricular outflow tract obstruction, which is associated with increased risk for heart failure and cardiovascular death (Ommen et al. J Am Coll Cardiol 46:470-476, 2005). HCM affects 1 in 500 people worldwide (Maron et al. Circulation 92:785-789, 1995).
Genetics
HCM is a heterogeneous genetic disease that is inherited in an autosomal dominant manner. It is caused by variants in various genes, most of which encode sarcomeric proteins. Defects in twelve genes, including TNNI3 (Kimura et al. Nat Genet 16:379-382, 1997) accounted for approximately 60% of all HCM cases. Variants were identified in both familial and sporadic cases, with similar distribution. Variants identified in sporadic cases were either nonpenetrant or occurred de novo. Some patients with severe phenotype were shown to have more than one variant, either in two different genes or in the same gene (Richard et al. Circulation 107:2227-2232, 2003). All documented causative variants in TNNI3 in patients with HCM are missense variants and small deletions. In addition to HCM, TNNI3 variants have been implicated in familial restrictive cardiomyopathy (Mogensen et al. J Clin Invest 111:209-216, 2003) and dilated cardiomyopathy (Carballo et al. Circ Res 105:375-382, 2009).
The TNNI3 gene encodes the troponin I subunit, which is one of the 3 subunits that form the troponin complex of the thin filaments of striated muscles. Troponin I is exclusively expressed in cardiac muscle.
Clinical Sensitivity - Sequencing with CNV PGxome
This test will detect variants in ~5% of patients with HCM (Cirino and Ho, GeneReviews, 2009). Sensitivity of this test for RCM and DCM is not known.
Testing Strategy
This test provides full coverage of all coding exons of the TNNI3 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 symptoms suggestive of hypertrophic cardiomyopathy, restrictive cardiomyopathy, and dilated cardiomyopathy. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in TNNI3.
Patients with symptoms suggestive of hypertrophic cardiomyopathy, restrictive cardiomyopathy, and dilated cardiomyopathy. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in TNNI3.
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| TNNI3 | 191044 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Diseases
| Name | Inheritance | OMIM ID |
|---|---|---|
| Cardiomyopathy, Familial Restrictive, 1 | AD | 115210 |
| Dilated Cardiomyopathy 1FF | 613286 | |
| Dilated Cardiomyopathy 2A | AR | 611880 |
| Familial Hypertrophic Cardiomyopathy 7 | AD | 613690 |
Related Tests
| Name |
|---|
| Comprehensive Cardiac Arrhythmia Panel |
| Comprehensive Cardiology Panel |
| Sudden Cardiac Arrest Panel |
Citations
- Carballo, S., et.al. (2009). "Identification and functional characterization of cardiac troponin I as a novel disease gene in autosomal dominant dilated cardiomyopathy." Circ Res 105(4): 375-82. PubMed ID: 19590045
- Cirino, A.L., Ho, C. (2009). "Familial Hypertrophic Cardiomyopathy Overview." PubMed ID: 20301725
- Fifer MA, Vlahakes GJ. 2008. Management of symptoms in hypertrophic cardiomyopathy. Circulation 117: 429-439. PubMed ID: 18212300
- Kimura, A., et.al. (1997). "Mutations in the cardiac troponin I gene associated with hypertrophic cardiomyopathy." Nat Genet 16(4): 379-82. PubMed ID: 9241277
- Maron BJ, Bonow RO, Cannon RO 3rd, Leon MB, Epstein SE. 1987. Hypertrophic cardiomyopathy. Interrelations of clinical manifestations, pathophysiology, and therapy (1). N. Engl. J. Med. 316: 780-789. PubMed ID: 3547130
- Maron, B. J., et.al. (1995). "Prevalence of hypertrophic cardiomyopathy in a general population of young adults. Echocardiographic analysis of 4111 subjects in the CARDIA Study. Coronary Artery Risk Development in (Young) Adults." Circulation 92(4): 785-9. PubMed ID: 7641357
- Mogensen, J., et.al. (2003). "Idiopathic restrictive cardiomyopathy is part of the clinical expression of cardiac troponin I mutations." J Clin Invest 111(2): 209-16. PubMed ID: 12531876
- Ommen SR, Maron BJ, Olivotto I, Maron MS, Cecchi F, Betocchi S, Gersh BJ, Ackerman MJ, McCully RB, Dearani JA, Schaff HV, Danielson GK, Tajik AJ, Nishimura RA. 2005. Long-term effects of surgical septal myectomy on survival in patients with obstructive hypertrophic cardiomyopathy. J. Am. Coll. Cardiol. 46: 470-476. PubMed ID: 16053960
- Richard P, Charron P, Carrier L, Ledeuil C, Cheav T, Pichereau C, Benaiche A, Isnard R, Dubourg O, Burban M, Gueffet JP, Millaire A, Desnos M, Schwartz K, Hainque B, Komajda M; EUROGENE Heart Failure Project. 2003. Hypertrophic cardiomyopathy: distribution of disease genes, spectrum of mutations, and implications for a molecular diagnosis strategy. Circulation 107: 2227-2232. PubMed ID: 12707239
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
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ORDER OPTIONS
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2) Select Additional Test Options
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