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)
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 is greater than 98%.
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
Hearing Loss and
GeneTests GeneReviews – DFNB1
Hearing Loss and
Chaib, H et al.: A
gene responsible for a sensorineural nonsyndromic recessive
deafness maps to chromosome 2p22-23. Hum.
Molec. Genet. 5:
PubMed ID: 8789454
Varga, R.;et al.: Non-syndromic
recessive auditory neuropathy is the result of mutations in the
otoferlin (OTOF) gene. (Letter) J.
Med. Genet. 40:
PubMed ID: 12525542