Usher Syndrome Type IF

Test Details

Use

Detect Usher syndrome type IF

Special Instructions

If cultured cells are needed, an additional 7-12 days may be required. Additional culture fee may be included.

Methodology

DNA analysis

Additional Information

Usher syndrome type IF occurs at increased frequency in individuals of Ashkenazi Jewish descent, with a carrier frequency of 1 in 141. This type of Usher syndrome causes profound deafness at birth, severe balance problems, as well as vision impairment. Blindness progresses over time. Children with this disorder are slow to sit without support and typically don't walk independently before 18 months. Decline in visual acuity typically begins by age 10. Currently, there is no treatment. Couples who are planning a pregnancy or who are already pregnant may decide to have testing to find out whether they are carriers and at risk of having a baby with Usher syndrome type IF. Usher syndrome type IF mutation analysis tests for one mutation for a 75% carrier detection rate in the Ashkenazi Jewish population.

Specimen Requirements

Information on collection, storage, and volume

Specimen

Whole blood, amniotic fluid, chorionic villus sample (CVS) (Submission of maternal blood is required for fetal testing.), or LabCorp buccal swab kit (Buccal swab collection kit contains instructions for use of a buccal swab.)

Volume

7 mL whole blood, 10 mL amniotic fluid, 20 mg CVS, or LabCorp buccal swab kit

Minimum Volume

3 mL whole blood, 5 mL amniotic fluid, 10 mg CVS, or two buccal swabs

Container

Lavender-top (EDTA) tube, yellow-top (ACD) tube, sterile plastic conical tube or two confluent T-25 flasks for fetal testing, or LabCorp buccal swab kit

Storage Instructions

Maintain specimen at room temperature.