Limb Girdle Muscular Dystrophy, Type 2E (LGMD2E) via the SGCB Gene
Summary and Pricing 
Test Method
Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes| Test Code | Test Copy Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
|---|---|---|---|---|---|
| 7817 | SGCB | 81405 | 81405,81479 | $990 | Order Options and Pricing |
Pricing Comments
Testing run on PG-select capture probes includes CNV analysis for the gene(s) on the panel but does not permit the optional add on of exome-wide CNV analysis. Any of the NGS platforms allow reflex to other clinically relevant genes, up to whole exome or whole genome sequencing depending upon the base platform selected for the initial test.
An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.
This test is also offered via a custom panel (click here) on our exome or genome backbone which permits the optional add on of exome-wide CNV or genome-wide SV analysis.
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
Variants in the SGCB gene cause limb girdle muscular dystrophy type 2E (LGMD2E; Lim et al. 1995). LGMD2E presents with a progressive clinical course and limb weakness. Proximal muscles are affected more than distal muscles. Severe cardiomyopathy has been associated with LGMD2E (Barresi et al. 2000; Fanin et al. 2003). Calf hypertrophy may be evident and scoliosis and contractures may occur later in the course of the disease. Serum creatine kinase levels are typically elevated, and muscle biopsies demonstrate a dystrophic process. Immunofluorescence or western blot analysis will detect absence or reduction of β-sarcoglycan but normal dystrophin staining. Secondary deficiency of the other sarcoglycans may be observed (Bonnemann et al. 1995).
Genetics
LGMD2E is inherited in an autosomal recessive manner. The SGCB gene encodes β-sarcoglycan, a membrane-spanning subunit of the sarcoglycan complex and a component of the dystrophin-glycoprotein complex. Autosomal recessive limb-girdle muscular dystrophy (LGMD2) is a genetically and clinically diverse group of muscular dystrophies. To date, 12 genes have been identified that are involved in subtypes LGMD2A-2L (see for example Laval and Bushby 2004; Gordon et al. 2009). A negative SGCB sequencing result does not rule out a diagnosis of limb girdle muscular dystrophy when classic clinical findings are present. A comprehensive approach including epidemiology, medical history, clinical exam, muscle biopsy and other labs, and genetic testing is recommended for precise diagnosis of the limb girdle muscular dystrophies (Guglieri and Bushby 2009).
Clinical Sensitivity - Sequencing with CNV PG-Select
Variants in the sarcoglycans account for about two-thirds of all childhood-onset recessive LGMD (Vainzof et al. 1999). In a cohort of 556 Italian and American sarcoglycanopathy patients, Duggan et al. (1997) found eight with SGCB variants. In LGMD2E patients reported by Moore et al. (2006) the c.341C>T (p.Ser114Phe) SGCB variant was found on 9 of 26 mutant alleles in 13 unrelated patients, making it the most common SGCB allele in patients from the USA. This variant was also identified on 5 of 6 mutant alleles in three Dutch LGMD2E patients (Ginjaar et al. 2000). In the Amish from Southern Indiana, a p.Thr151Arg variant has been shown to cause a mild form of LGMD2E in 11 families sharing a common haplotype (Duclos et al. 1998).
Testing Strategy
This test provides full coverage of all coding exons of the SGCB gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.
Indications for Test
Individuals with symptoms consistent with LGMD. Individuals with immunofluorescence results demonstrating reduced staining of β-sarcoglycan in muscle. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in SGCB.
Individuals with symptoms consistent with LGMD. Individuals with immunofluorescence results demonstrating reduced staining of β-sarcoglycan in muscle. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in SGCB.
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| SGCB | 600900 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Disease
| Name | Inheritance | OMIM ID |
|---|---|---|
| Limb-Girdle Muscular Dystrophy, Type 2E | AR | 604286 |
Related Test
| Name |
|---|
| Dilated Cardiomyopathy and Limb-Girdle Muscular Dystrophy Type 2F via the SGCD Gene |
Citations
- Bönnemann CG, Modi R, Noguchi S, Mizuno Y, Yoshida M, Gussoni E, McNally EM, Duggan DJ, Angelini C, Hoffman EP. 1995. Beta-sarcoglycan (A3b) mutations cause autosomal recessive muscular dystrophy with loss of the sarcoglycan complex. Nat. Genet. 11: 266-273. PubMed ID: 7581449
- Barresi R, Blasi C Di, Negri T, Brugnoni R, Vitali A, Felisari G, Salandi A, Daniel S, Cornelio F, Morandi L. 2000. Disruption of heart sarcoglycan complex and severe cardiomyopathy caused by β sarcoglycan mutations. Journal of medical genetics 37: 102-107. PubMed ID: 10662809
- Bueno MRP, Moreira ES, Vainzof M, Chamberlain J, Marle SK, Pereira L, Akiyama J, Roberds SL, Campbell KP, Zatz M. 1995. A common missense mutation in the adhalin gene in three unrelated Brazilian families with a relatively mild form of autosomal recessive limb-girdle muscular dystrophy. Human molecular genetics 4: 1163-1167. PubMed ID: 8528203
- Duclos F, Broux O, Bourg N, Straub V, Feldman GL, Sunada Y, Lim LE, Piccolo F, Cutshall S, Gary F, Quetier F, Kaplan JC, et al. 1998. Beta-sarcoglycan: genomic analysis and identification of a novel missense mutation in the LGMD2E Amish isolate. Neuromuscul. Disord. 8: 30-38. PubMed ID: 9565988
- Duggan DJ, Gorospe JR, Fanin M, Hoffman EP, Angelini C. 1997. Mutations in the sarcoglycan genes in patients with myopathy. N. Engl. J. Med. 336: 618-624. PubMed ID: 9032047
- Erynn Gordon, et.al. (2009). "Limb-Girdle Muscular Dystrophy Overview."
- Fanin M, Melacini P, Boito C, Pegoraro E, Angelini C. 2003. LGMD2E patients risk developing dilated cardiomyopathy. Neuromuscular Disorders 13: 303-309. PubMed ID: 12868499
- Ginjaar HB, Kooi AJ van der, Ceelie H, Kneppers AL, Meegen M van, Barth PG, Busch HF, Wokke JH, Anderson LV, Bönnemann CG, Jeanpierre M, Bolhuis PA, et al. 2000. Sarcoglycanopathies in Dutch patients with autosomal recessive limb girdle muscular dystrophy. J. Neurol. 247: 524-529. PubMed ID: 10993494
- Guglieri M, Bushby K. 2008. How to go about diagnosing and managing the limb-girdle muscular dystrophies. Neurology India 56:271-280. PubMed ID: 18974553
- Laval SH, Bushby KMD. 2004. Limb-girdle muscular dystrophies - from genetics to molecular pathology. Neuropathology and Applied Neurobiology 30: 91-105. PubMed ID: 15043707
- Moore SA, Shilling CJ, Westra S, Wall C, Wicklund MP, Stolle C, Brown CA, Michele DE, Piccolo F, Winder TL, Stence A, Barresi R, King N, King W, Florence J, Campbell KP, Fenichel GM, Stedman HH, Kissel JT, Griggs RC, Pandya S, Mathews KD, Pestronk A, Serrano C, Darvish D, Mendell JR. 2006. Limb-girdle muscular dystrophy in the United States. J Neuropathol Exp Neurol 65: 995-1003. PubMed ID: 17021404
- Vainzof M, Passos-Bueno MR, Pavanello RC, Marie SK, Oliveira AS, Zatz M. 1999. Sarcoglycanopathies are responsible for 68% of severe autosomal recessive limb-girdle muscular dystrophy in the Brazilian population. J Neurol Sci 164: 44-49. PubMed ID: 10385046
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
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