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 GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
7567 ADGRG1 81479 81479,81479 $640 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
7567ADGRG181479 81479 $640 Order Options and Pricing

Pricing Comments

This test is also offered via our exome backbone with CNV detection (click here). The exome-based test may be higher priced, but permits reflex to the entire exome or to any other set of clinically relevant genes.

A 25% additional charge will be applied to STAT orders. View STAT turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.

Turnaround Time

18 days on average

EMAIL CONTACTS

Genetic Counselors

Geneticist

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).

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.

Clinical Sensitivity - Sequencing with CNV PG-Select

Sensitivity of this test is currently unknown.

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.

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.
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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


Specimen Types

Specimen Requirements and Shipping Details

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ORDER OPTIONS

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