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Cohen Syndrome via the VPS13B (COH1) 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
15211 VPS13B 81408 81408,81407 $640 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
15211VPS13B81408 81408,81407 $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.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Turnaround Time

18 days on average for standard orders or 13 days 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.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Li Fan, MD, PhD, FCCMG, FACMG

Clinical Features and Genetics

Clinical Features

Cohen syndrome (OMIM 216550) is characterized clinically by developmental delay, early-onset myopia, joint laxity, and a characteristic facies (Hennies et al. Am J Hum Genet 75:138-145, 2004). In the Finnish population, where Cohen syndrome is relatively more common, patients uniformly exhibit microcephaly, developmental delay, retinal dystrophy, neutropenia, joint laxity, and characteristic facies (Kolehmainen et al. Am J Hum Genet 72:1359-1369, 2003). In patients from a more diverse geographic region, however, microcephaly, neutropenia, retinopathy in school-aged children, and the typical facies are not constant findings (Hennies et al., 2004; Seifert et al. J Med Genet 43:e22, 2006). Developmental delay varies in severity from profound to mild mental retardation (Kivitie-Kallio and Norio. Am J Med Genet 102:125-135, 2001), and most patients have a cheerful disposition. Patients also have motor clumsiness, muscle weakness, and hypotonia beyond infancy. Microcephaly, when present is of postnatal onset. Facial dysmorphism includes high, arched eyelids; mildly downslanting palpebral fissures; a short philtrum; open mouth with prominent upper incisors; high, arched narrow palate; and large ears. Other features sometimes occurring in Cohen syndrome include slender fingers, thick hair with low hairline, delayed puberty, and a high-pitched voice. Obesity in Cohen syndrome patients has been found to be unremarkable (Kolehmainen et al., 2003).

Genetics

Cohen syndrome is inherited as an autosomal recessive disorder, most often involving private variants. Allelic heterogeneity underlies the variability in observed clinical phenotypes. Truncating VPS13B (COH1) variants are the most abundant class of variant and they are distributed throughout the gene.

Clinical Sensitivity - Sequencing with CNV PG-Select

Clinical sensitivity of the VPS13B (COH1) sequencing test has been shown to be high in patients from wide geographic origins with highly variable clinical phenotypes. For example, Hennies et al. (2004) found two variants in probands from all twelve families originating from countries in Eastern and Southern Europe, South America, and the Middle East. Similarly, Seifert et al. (2006) found two variants in all but one proband from sixteen families with diverse ethnic origins. A single mutant VPS13B allele was found in the other proband.

Testing Strategy

This test is performed using Next-Generation sequencing with additional Sanger sequencing as necessary.

This test provides full coverage of all coding exons of the VPS13B gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.

Indications for Test

Individuals with clinical features resembling Cohen syndrome. Because of the broad clinical spectrum documented for this disorder, not all variant-proven cases will have a classic presentation. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in VPS13B.

Gene

Official Gene Symbol OMIM ID
VPS13B 607817
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Cohen Syndrome AR 216550

Citations

  • Hennies, H. C., et.al. (2004). "Allelic heterogeneity in the COH1 gene explains clinical variability in Cohen syndrome." Am J Hum Genet 75(1): 138-45. PubMed ID: 15154116
  • Kivitie-Kallio, S., Norio, R. (2001). "Cohen syndrome: essential features, natural history, and heterogeneity." Am J Med Genet 102(2): 125-35. PubMed ID: 11477603
  • Kolehmainen, J., et.al. (2003). "Cohen syndrome is caused by mutations in a novel gene, COH1, encoding a transmembrane protein with a presumed role in vesicle-mediated sorting and intracellular protein transport." Am J Hum Genet 72(6): 1359-69. PubMed ID: 12730828
  • Seifert, W., et.al. (2006). "Mutational spectrum of COH1 and clinical heterogeneity in Cohen syndrome." J Med Genet 43(5): e22. PubMed ID: 16648375

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


Specimen Types

Specimen Requirements and Shipping Details

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ORDER OPTIONS

View Ordering Instructions

1) Select Test Method (Backbone)


1) Select Test Type


2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
Total Price: $
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