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Frequently Asked Questions

 

Contact:
The University of Iowa
5270 CBRB
Iowa City, IA 52242
phone: 319-335-6623
fax:     319-353-5869

 

OTOF
The Clinical Diagnostics Service of the Molecular Otolaryngology & Renal Research Laboratories is a Joint Commission-approved CLIA-accredited diagnostic laboratory that offers mutation screening of several genes.

DFNB9 (OMIM# 601071)
The gene OTOF causes autosomal recessive nonsyndromic hearing loss at the DFNB9 locus, which maps to chromosome 2p23-p22.

OTOF (OMIM# *603681)
OTOF is a gene of 48 exons that encodes a transmembrane protein of 1230 amino acids called otoferlin.  Otoferlin is expressed in multiple cell types within the cochlea.  More than 24 mutations in OTOF have been reported and are associated with autosomal recessive nonsyndromic sensorineural hearing loss.  Often, otoacoustic emissions (OAEs) are present while pure tone audiometry or auditory brain stem responses (ABRs) are grossly abnormal, features characteristic of auditory neuropathy.

MORL screening methodology
Oligonucleotide primers have been designed for amplification of each exon including intron/exon boundaries of OTOF. These amplimers are used for bi-directional sequencing.

Sensitivity
Sensitivity is greater than 98%.

Turn-around time
Turn around time is approximately 3 months (Average TAT - 81 days).

Indications for screening
This test is appropriate for any person with congenital hearing impairment and the diagnosis of auditory neuropathy, if the family history is consistent with autosomal recessive inheritance.  It is also appropriate for persons with congenital hearing impairment and a family history consistent with autosomal recessive inheritance if GJB2 mutation screening is negative.

GeneTests  GeneReviews – DFNB9 - Nonsyndromic Hearing Loss and Deafness

GeneTests  GeneReviews – DFNB1 - Nonsyndromic Hearing Loss and Deafness

References
Chaib, H et al.:  A gene responsible for a sensorineural nonsyndromic recessive deafness maps to chromosome 2p22-23. Hum. Molec. Genet. 5: 155-158, 1996.
PubMed ID:  8789454 
PubMed Search

Varga, R.;et al.:  Non-syndromic recessive auditory neuropathy is the result of mutations in the otoferlin (OTOF) gene. (Letter) J. Med. Genet. 40: 45-50, 2003.
PubMed ID: 12525542
PubMed Search