Joubert and Meckel-Gruber Syndromes via the CC2D2A 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 | |
|---|---|---|---|---|---|
| 15235 | CC2D2A | 81479 | 81479,81479 | $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
Joubert syndrome (JS) (OMIM 213300) is marked by hypotonia, abnormal ocular movements, neonatal respiratory difficulties, mental retardation, hypoplasia of the cerebellar vermis, and malformation of the brainstem. The brain malformations lead to the "molar tooth sign" on cranial MRI, which is the hallmark clinical feature of JS. Other variable JS features include cystic kidneys, nephronophthisis, retinal dystrophy, ocular coloboma, occipital encephalocele, polydactyly, ataxia, and hepatic fibrosis. For more information, see Parisi and Glass (GeneReviews, 2006) and Parisi et al. (Eur J Hum Genet 15:511-521, 2007).
Meckel-Gruber syndrome (MKS) (OMIM 249000) is characterized by occipital encephalocele, polycystic kidneys, hepatic developmental defects, and postaxial polydactyly (Alexiev et al. Arch Pathol Lab Med 130:1236-1238, 2006). MKS is a common cause of prenatal echogenic kidneys (Chaumoitre et al. Ultrasound Obstet Gynecol 28:911-917, 2006). Nearly all MKS infants are stillborn or die shortly after birth. The clinical features of JS and MKS clearly overlap.
Genetics
JS and MKS both exhibit autosomal recessive inheritance. Both disorders have high levels of locus heterogeneity with 7 JS genes (TMEM67/MKS3, AHI1, CC2D2A, CEP290, RPGRIP1L, ARL13B, NPHP1) and 5 MKS genes (MKS1, TMEM67/MKS3, CC2D2A, CEP290, RPGRIP1L) identified to date. Additional genes are likely to be identified in future. Both JS and MKS are ciliopathies, meaning that they are caused by variants in genes which encode proteins involved in cilia/centrosome structure and function (Hildebrandt and Otto Nat Rev Genet 6:928-940, 2005; http://v3.ciliaproteome.org/cgi-bin/index.php). CC2D2A has recently been reported to be mutated in both JS and MKS (Gorden et al. Am J Hum Genet 83:1-13, 2008; Noor et al. Am J Hum Genet 82:1011-1018, 2008; Noor et al. Am J Hum Genet 83:656, 2008; and Tallila et al. Am J Hum Genet 82:1361-1367, 2008). About 10 causative variants, a mix of nonsense, splicing, frameshift, and missense, have been reported.
Clinical Sensitivity - Sequencing with CNV PG-Select
The following are the approximate fractions of patients with variants in the indicated genes. JS: TMEM67/MKS3 10%, AHI1 10%, CC2D2A 10%, CEP290 10%, RPGRIP1L 2%, ARL13B 2%, NPHP1 2%. MKS: MKS1 15%, TMEM67/MKS3 15%, CC2D2A 10%, CEP290 10%, RPGRIP1L 2%.
Testing Strategy
This test is performed using Next-Gen sequencing with additional Sanger sequencing as necessary.
This test provides full coverage of all coding exons of the CC2D2A 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.
Indications for Test
Patients with symptoms consistent with JS or MKS are candidates. Conclusive connections between clinical features and mutated genes have not yet been made. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in CC2D2A.
Patients with symptoms consistent with JS or MKS are candidates. Conclusive connections between clinical features and mutated genes have not yet been made. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in CC2D2A.
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| CC2D2A | 612013 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Diseases
| Name | Inheritance | OMIM ID |
|---|---|---|
| Joubert Syndrome 9 | AR | 612285 |
| Meckel Syndrome 6 | AR | 612284 |
Citations
- Alexiev BA, Lin X, Sun CC, Brenner DS. 2006. Meckel-Gruber syndrome: pathologic manifestations, minimal diagnostic criteria, and differential diagnosis. Arch. Pathol. Lab. Med. 130: 1236-1238. PubMed ID: 16879033
- Chaumoitre K, Brun M, Cassart M, Maugey-Laulom B, Eurin D, Didier F, Avni EF. 2006. Differential diagnosis of fetal hyperechogenic cystic kidneys unrelated to renal tract anomalies: A multicenter study. Ultrasound Obstet Gynecol 28: 911–917. PubMed ID: 17094077
- Gorden, N. T., et.al. (2008). "CC2D2A is mutated in Joubert syndrome and interacts with the ciliopathy-associated basal body protein CEP290." Am J Hum Genet 83(5): 559-71. PubMed ID: 18950740
- Hildebrandt, F., Otto, E. (2005). "Cilia and centrosomes: a unifying pathogenic concept for cystic kidney disease?." Nat Rev Genet 6(12): 928-40. PubMed ID: 16341073
- Noor, A., et.al. (2008). "Addendum. CC2D2A, encoding a coiled-coil and C2 domain protein, causes autosomal-recessive mental retardation with retinitis pigmentosa." Am J Hum Genet 83(5): 656. PubMed ID: 19068953
- Noor, A., et.al. (2008). "CC2D2A, encoding a coiled-coil and C2 domain protein, causes autosomal-recessive mental retardation with retinitis pigmentosa." Am J Hum Genet 82(4): 1011-8. PubMed ID: 18387594
- Parisi M, Glass I. 2013. Joubert Syndrome and Related Disorders. In: Pagon RA, Adam MP, Ardinger HH, Bird TD, Dolan CR, Fong C-T, Smith RJ, and Stephens K, editors. GeneReviews(®), Seattle (WA): University of Washington, Seattle. PubMed ID: 20301500
- Parisi MA, Doherty D, Chance PF, Glass IA. 2007. Joubert syndrome (and related disorders) (OMIM 213300). Eur. J. Hum. Genet. 15: 511–521. PubMed ID: 17377524
- Tallila, J., et.al. (2008). "Identification of CC2D2A as a Meckel syndrome gene adds an important piece to the ciliopathy puzzle." Am J Hum Genet 82(6): 1361-7. PubMed ID: 18513680
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
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