Specimen:

Whole Blood

Collection Medium:

Minimum:

Preferred Minimum:  8 mL whole blood
Absolute Minimum:  4 mL whole blood

Analytic Time:

3 months

Reference Range:

None detected

Interpretive Data:

DFNA2
Two genes are responsible for autosomal dominant nonsyndromic 
sensorineural hearing loss at the DNFA2 locus, KCNQ4 and GJB3. Both of 
these genes map to chromosome 1p34-p35.

KCNQ4
KCNQ4 is voltage-gated potassium channel expressed in the outer hair 
cells of the cochlea.  The gene has 14 exons that encode a 695 amino 
acid protein.  Mutations in KCNQ4 are found persons with 
high-frequency, autosomal dominant, nonsyndromic sensorineural hearing 
loss.  At least eight different mutations in KCNQ4 have been identified 
in families segregating autosomal dominant nonsyndromic hearing loss.

Sensitivity is greater than 98%.

Comments:

Please print, complete and submit the Deafness Testing Requisition 
from the Molecular Otolaryngology & Renal Research Laboratory, to 
Specimen Control/Mailouts with the specimen and the Epic Requisition.

Methodology:

Screening for KCNQ4 is performed via DHPLC and sequencing.  
Oligonucleotide primers have been designed to amplify each exon.  
Amplified samples are run on the DHPLC; abnormal elution profiles are 
sequenced to identify specific mutations.  Exons carrying known SNPs 
are directly sequenced.

CPT Code:

83891, 83894, 83898 (x12), 83903 (x12), 83904 (x10), 83912