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Paediatric Laboratory Medicine

Branchio-Oto-Renal Syndrome: EYA1 Sequencing

Clinical Significance

Branchio-oto-renal (BOR) syndrome is an autosomal dominant condition characterized by branchial, otic and renal anomalies. Branchial arch defects include cysts and fistulae. Otologic findings include sensorineural, conductive or mixed hearing loss with malformations of the outer, middle and inner ear. Renal malformations range from mild renal hypoplasia to bilateral renal agenesis, with some individuals progressing to end-stage renal disease later in life. Patients with BOR syndrome may show variability in clinical features due to incomplete penetrance and variable expressivity.

BOR syndrome is genetically heterogeneous; however, mutations in the EYA1 gene at 8q13.3 have been implicated in about 40 per cent of BOR syndrome cases. Of BOR syndrome patients with EYA1 mutations, approximately 75–80 per cent have point mutations in the EYA1 gene while the remainder may have rearrangements of the gene causing large deletions or insertions. Molecular testing for BOR syndrome consists of complete sequencing of the coding region and flanking exon/intron boundaries of the EYA1 gene to detect point mutations, and quantitative testing of the EYA1 gene to detect larger deletions or duplications.

BOR syndrome is present when an individual has one copy of the defective EYA1 gene. Affected individuals have a 50 per cent chance of transmitting the disorder to each child. There is a 50 per cent chance that the affected individual’s offspring will not be affected with BOR syndrome.

Test Name

Branchio-Oto-Renal Syndrome: EYA1 Sequencing

Alternate Name/ Synonym

  • Brachiootorenal Spectrum Disorders
  • Melnick-Fraser syndrome

Gene Name

  • EYA1

Alternate Gene Name

BOR, BOP

Test Code

BOR

Division

Molecular Genetics

Method

Sequencing

External Proficiency Testing

CAP

Turn Around Time

2 weeks (Prenatal samples), 2-3 weeks (Pregnancy/Urgent samples), 4-6 weeks (Routine)

Protein

Eyes absent homolog 1

Disease/Condition

Branchio-Oto-Renal Syndrome

Specimen Type

Blood; extracted DNA is not accepted for Branchio-Oto-Renal Syndrome: EYA1 Deletion/Duplication Analysis

If sending a prenatal sample, please contact the laboratory prior to sending sample to discuss sample requirements.

For details about specimen requirements, please refer to: Specimen Type & Requirements (PDF).

Minimum Specimen Requirements

5-10 mL EDTA or ACD
0.5 mL EDTA (neonate)

Storage/Transportation

Room Temperature

Special Requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Approval is not required

CPT Codes

81406

Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Canada
Phone: 416-813-7200
Phone: 1-855-381-3212

Interpretation

Interpretation is provided in report

Information Sheet: Branchio-Oto-Renal Syndrome