Bilateral frontoparietal polymicrogyria (BFPP) via the ADGRG1 (GPR56) 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 | |
|---|---|---|---|---|---|
| 7567 | ADGRG1 | 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
Polymicrogyria (PMG) is a malformation of cortical development characterized by numerous small gyri with abnormal lamination (Barkovich et al. Neurology 65:1873-1887, 2005). Bilateral frontoparietal polymicrogyria (BFPP; OMIM 606854) is a severe form of PMG. BFPP is a neuronal migration defect mainly characterized by severe mental retardation, motor developmental delay, language difficulties, seizures, dysconjugate gaze, ataxia, bilateral polymicrogyria (cobblestone malformation) with anterior to posterior gradient, bilateral patchy white matter signal changes, and brainstem and cerebellar hypoplasia (Piao et al. Am J Hum Genet 70:1028-1033, 2002; Chang et al. Ann Neurol 53:596-606, 2003; Piao et al. Ann Neurol 58:680-687, 2005). Of note, BFPP developmental delay and gaze issues present in early childhood, whereas seizures may not begin until after 5 years of age (Piao et al. Science 303:2033-2036, 2004).
Genetics
Bilateral frontoparietal polymicrogyria (BFPP) is inherited as an autosomal recessive disorder and is caused by variants in the ADGRG1 (GPR56) gene (Piao et al. 2002). ADGRG1 gene encodes an orphan G protein-coupled receptor (GPCR) with seven transmembrane domains and a large extracellular domain characterized by extracellular cysteine box and hydrophilic mucin-rich domains (Piao et al. 2004). It has been proposed that GPCR signaling plays a critical role in regional development of the human cerebral cortex. GPCR appears to be specifically involved in regulating cortical patterning (Piao et al. 2004). A mix of missense, splice site, and frameshift variants has been reported in the ADGRG1 gene (Piao et al. 2004; Piao et al. 2005). In addition, a heterozygous gross deletion of 16q12.1-q21 has been reported in one patient with clinical diagnosis consistent with BFPP. However, a second plausible causative variant was not found in that patient (Borgatti et al. Clin Genet 76:573-576, 2009).
Clinical Sensitivity - Sequencing with CNV PG-Select
Sensitivity of this test is currently unknown.
Testing Strategy
This test provides full coverage of all coding exons of the ADGRG1 gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.
Indications for Test
Candidates for this test are patients with symptoms consistent with bilateral frontoparietal polymicrogyria and family members of patients who have known ADGRG1 variants.
Candidates for this test are patients with symptoms consistent with bilateral frontoparietal polymicrogyria and family members of patients who have known ADGRG1 variants.
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| ADGRG1 | 604110 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Disease
| Name | Inheritance | OMIM ID |
|---|---|---|
| Polymicrogyria, Bilateral Frontoparietal | AR | 606854 |
Citations
- Barkovich, A. J., et.al. (2005). "A developmental and genetic classification for malformations of cortical development." Neurology 65(12): 1873-87. PubMed ID: 16192428
- Borgatti, R., et.al. (2009). "Bilateral frontoparietal polymicrogyria (BFPP) syndrome secondary to a 16q12.1-q21 chromosome deletion involving GPR56 gene." Clin Genet 76(6): 573-6. PubMed ID: 19807741
- Chang, B. S., et.al. (2003). "Bilateral frontoparietal polymicrogyria: clinical and radiological features in 10 families with linkage to chromosome 16." Ann Neurol 53(5): 596-606. PubMed ID: 12730993
- Piao, X., et.al. (2002). "An autosomal recessive form of bilateral frontoparietal polymicrogyria maps to chromosome 16q12.2-21." Am J Hum Genet 70(4): 1028-33. PubMed ID: 11845408
- Piao, X., et.al. (2004). "G protein-coupled receptor-dependent development of human frontal cortex." Science 303(5666): 2033-6. PubMed ID: 15044805
- Piao, X., et.al. (2005). "Genotype-phenotype analysis of human frontoparietal polymicrogyria syndromes." Ann Neurol 58(5): 680-7. PubMed ID: 16240336
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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ORDER OPTIONS
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2) Select Additional Test Options
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