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Oculocutaneous Albinism Type 2 (OCAII) via the OCA2 Known Intragenic Gross Deletion

Summary and Pricing

Test Method

Targeted Deletion Testing via PCR
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
3738 OCA2 81479 81479 $250 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
3738OCA281479 81479(x1) $250 Order Options and Pricing

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 14 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.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Dana Talsness, PhD

Clinical Features and Genetics

Clinical Features

Oculocutaneous albinism (OCA) is an inherited disorder caused by deficiency in melanin synthesis that results in hypopigmentation of the skin, eyes, and hair. If the phenotype is mainly restricted to the eyes and the optic system, it is referred to as ocular albinism (OA) (Gargiulo et al. 2011). The reduction or complete absence of melanin pigment in the developing eye leads to foveal hypoplasia and misrouting of the optic nerves in the affected individuals (Oetting and King 1999). The eye and optic system abnormalities that are common to all types of albinism are nystagmus, photophobia, strabismus, moderate to severe impairment of visual acuity, reduced iris pigment with iris translucency, reduced retinal pigment with visualization of the choroidal blood vessels on ophthalmoscopic examination, refractive errors and altered visual evoked potentials (VEP). The degree of skin and hair hypopigmentation varies with the type of OCA (Lewis 2012). To date, four types of non-syndromic OCA (type I-IV) have been described. Among these, OCAII (tyrosinase-positive) is the most prevalent type and twice as common as compared to OCAI in African and African-American populations (Durham-Pierre et al. 1994), with estimated incidence of 1: 4,000-10,000. In the USA, the estimated prevalence of OCA2 is 1:36,000 (Grønskov et al. 2007).

Genetics

OCA is genetically heterogeneous. The major autosomal recessive forms OCA I and II are caused by genetic variations in TYR and OCA2, respectively. OCA2 (previously known as P-gene) encodes the integral melanosomal membrane protein, which is hypothesized to play an essential role in maintaining the pH of the melanosomes (Brilliant 2001). The frequency of OCAII is greatly increased in patients with Angelman and Prader-willi syndromes due to the deletion of chromosome 15q ( the region that comprises the OCA2 gene) (Lee et al. 1994). A gross deletion (reported as 2.7-kb interstitial deletion allele) of the OCA2 gene accounts for 65% and 92% of mutant alleles in two African countries, Zimbabwe and Cameroon, respectively (Puri et al. 1997). 

Clinical Sensitivity - Targeted Deletion

A known interstitial deletion allele (reported as ~2.7kb) of the OCA2 gene accounts for 65% and 92% of mutant alleles in two African countries, Zimbabwe and Cameroon, respectively (Puri et al. 1997).

Testing Strategy

This test involves amplification of patient DNA with a specific pair of PCR primers (P1 through P4) that flank the common OCA2 deletion. From chromosomes carrying the homozygous deletion, 1.4 and 1.8 kb PCR products are produced with P1 and P2, respectively. No PCR product is generated with P3 and P4 sets. In the case of heterozygous deletion, P1 and P2 give PCR products ~1.4 or 1.8 kb and P3 and P4 give PCR products ~0.6 or 1.1 kb. In normal chromosomes, only ~0.6 and 1.1 kb PCR products are generated by P3 and P4.

Indications for Test

African and African American individuals with the OCA II phenotype are candidates for this test.

Gene

Official Gene Symbol OMIM ID
OCA2 611409
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Citations

  • Brilliant MH. 2001. Pigment Cell Research. 14: 86-93. PubMed ID: 11310796
  • Durham-Pierre D. et al. 1994. Nature Genetics. 7: 176-9. PubMed ID: 7920637
  • Gargiulo A. et al. 2011. Investigative Ophthalmology & Visual Science. 52: 1281-9. PubMed ID: 20861488
  • Grønskov K. et al. 2007. Orphanet Journal of Rare Diseases. 2: 43. PubMed ID: 17980020
  • Iida R. et al. 2009. Cell Biochemistry and Function. 27: 323-7. PubMed ID: 19472299
  • Lee ST. et al. 1994. The New England Journal of Medicine. 330: 529-34. PubMed ID: 8302318
  • Lewis RA. 2012. Oculocutaneous Albinism Type 2. In: Pagon RA, Adam MP, Bird TD, Dolan CR, Fong C-T, and Stephens K, editors. GeneReviews™, Seattle (WA): University of Washington, Seattle. PubMed ID: 20301410
  • Oetting WS., King RA. 1999. Human Mutation. 13: 99-115. PubMed ID: 10094567
  • Puri N. et al. 1997. Human Genetics. 100: 651-6. PubMed ID: 9341887

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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