Icahn School of Medicine at Mount Sinai
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Genetic Testing Lab

Test Catalog Molecular Genetics Laboratory Usher 1F

Usher 1F

Test Description:
Usher syndrome (USH) is an autosomal recessive disorder characterized by bilateral sensorineural deafness and progressive loss of vision due to retinitis pigmentosa. It is the most frequent cause of deafness and concurrent blindness, with a prevalence of 1/16,000 to 1/50,000. USH can be classified into three clinical subtypes, the most severe of which is type 1 Usher syndrome (USH I), characterized by profound prelingual hearing loss, vestibular areflexia, and prepubertal onset of retinitis pigmentosa. Although the disorder is panethnic, and multiple causative genes have been identified, one mutation in the PCDH15 gene (p.R245X) has a carrier frequency of approximately 1 in 147 in the Ashkenazi Jewish population. Screening for one mutation will detect at least 75% of carriers in this population**. Carrier screening for USH I may be considered for individuals of Eastern European (Ashkenazi) Jewish ancestry before/during pregnancy.

** A carrier detection rate of 75% is lower than that of the other conditions offered on this panel. Please be aware of the limitations of this test.

References:
1. Ahmed ZM et al., (2003) The molecular genetics of Usher syndrome. Clin Genet. Jun;63(6):431-44.
2. Alagramam KN et al., (2001) Mutations in the novel protocadherin PCDH15 cause Usher syndrome type 1F. Hum Mol Genet. Aug 1;10(16):1709-18.
3. Ben-Yosef T et al., (2003) A mutation of PCDH15 among Ashkenazi Jews with the type 1 Usher syndrome. N Engl J Med. Apr 24;348(17):1664-70.
4. Petit C (2001) Usher syndrome: from genetics to pathogenesis. Annu Rev Genomics Hum Genet. 2:271-97.
5. Scott, S.A., Edelmann, L., Liu, L., Luo, M., Desnick, R.J. and Kornreich, R. Experience with carrier screening and prenatal diagnosis for sixteen Ashkenazi Jewish Genetic Diseases. Hum. Mutat. 31:1-11, 2010.

Specimen Requirements:
Two 5-10 ml tubes of anticoagulated blood. The preferred anticoagulant is EDTA (lavendar top tubes), ACD (yellow top) tubes are also accepted.

Shipping: Send at room temperature.

Turnaround Time: 10-14 days

CPT Codes: 83891, 83892x2, 83898, 83912, 83914

Consent and Requisition Forms: Carrier Screening Requisition and Consent [PDF]

Additional Information: Jewish Genetic Screening Brochure [PDF]

Related Tests: Ashkenazi Jewish Carrier Test Panel

Prior to ordering prenatal testing, please contact our laboratory at 212-241-7518 to discuss.