Waardenburg Syndrome Type IIA via the MITF 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
8401 MITF 81479 81479,81479 $640 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8401MITF81479 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.

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.

Once a specimen has started the testing process in our lab, the most accurate prediction of TAT will be displayed in the myPrevent portal as an Estimated Report Date (ERD) range. We calculate the ERD for each specimen as testing progresses; therefore the ERD range may differ from our published average TAT. View 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

Clinical Features and Genetics

Clinical Features

Waardenburg syndrome (WS) is an auditory-pigmentary disorder characterized by congenital sensorineural hearing loss and pigmentary abnormalities of the hair, including a white forelock, and pigmentary changes of the iris such as heterochromia. WS is classified into 4 main types depending on the clinical symptoms and has causative mutations in different genes (Pingault et al., 2010).

WS I : Auditory-pigmentary abnormalities along with dystopia canthorum (lateral displacement of the inner canthi), caused by mutations in PAX3.

WS II : Auditory-pigmentary abnormalities without dystopia canthorum, caused by mutations in MITF, SNAI2, and SOX10.

WS III : Type I with musculo-skeletal abnormalities of the upper limb (Klein-Waardenburg syndrome), caused by mutations in PAX3.

WS IV : Type II with Hirschsprung disease (Waardenburg-Shah syndrome), caused by mutations in EDN3, EDNRB, and SOX10.

WS type II is typified by sensorineural hearing loss and heterochromia iridumis observed in approximately 77% and 47% of affected individuals respectively, and is much more common than WS type I (Liu et al., 1995). Dystopia canthorum is NOT observed in WS II. Other clinical manifestations such as the classic white forelock are more common in WS1.

Genetics

WS type II is an autosomal dominant syndrome caused by heterozygous mutations in the MITF gene. MITF, the microphthalmia-associated transcription factor, helps control the development and function of pigment-producing cells called melanocytes, which produce the pigment melanin, contributing to hair, eye, and skin color. Melanocytes are also found in the inner ear and play an important role in hearing. Mutations in MITF alter protein dimerization impacting melanocyte development (Widlund and Fisher, 2003). Shortage of melanocytes results in hypopigmentation and hearing loss characteristic of Waardenburg syndrome. It is estimated that MITF mutations are observed in 15% of individuals with WS2 (Read and Newton, 1997). Mutations include missense, truncating, splicing alterations along with deletions and insertions. Digenic inheritance of WS with ocular albinism has been suggested (Chiang et al., 2009). Mutations in MITF are also known to be causative for Tietz syndrome (Smith et al., 2000).

Clinical Sensitivity - Sequencing with CNV PG-Select

It is estimated that MITF mutations are observed in 15% of individuals with WS2 (Read and Newton, 1997). Molecular genetic testing by sequencing of MITF detects more than 90% of disease-causing mutations.

Testing Strategy

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

Indications for Test

Diagnostic criteria for Waardenburg syndrome type II (WSII) were outlined (Liu et al. 1995) and include three important indicators: Congenital sensorineural hearing loss, Complete heterochromia iridum (irides of different color), and Absence of Dystopia canthorum.

Gene

Official Gene Symbol OMIM ID
MITF 156845
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

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Citations

  • Chiang P-W, Spector E, McGregor TL. 2009. Evidence suggesting digenic inheritance of Waardenburg syndrome type II with ocular albinism. Am. J. Med. Genet. A 149A: 2739–2744. PubMed ID: 19938076
  • Liu XZ, Newton VE, Read AP. 1995. Waardenburg syndrome type II: phenotypic findings and diagnostic criteria. Am. J. Med. Genet. 55: 95–100. PubMed ID: 7702105
  • Pingault V, Ente D, Dastot-Le Moal F, Goossens M, Marlin S, Bondurand N. 2010. Review and update of mutations causing Waardenburg syndrome. Human Mutation 31: 391–406. PubMed ID: 20127975
  • Read AP, Newton VE. 1997. Waardenburg syndrome. Journal of medical genetics 34: 656–665. PubMed ID: 9279758
  • Smith SD, Kelley PM, Kenyon JB, Hoover D. 2000. Tietz syndrome (hypopigmentation/deafness) caused by mutation ofMITF. Journal of medical genetics 37: 446–448. PubMed ID: 10851256
  • Widlund HR, Fisher DE. 2003. Microphthalamia-associated transcription factor: a critical regulator of pigment cell development and survival. Oncogene 22: 3035–3041. PubMed ID: 12789278

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.

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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