A mouse model for nonsyndromic deafness (DFNB12) links hearing loss to defects in tip links of mechanosensory hair cells.
Deafness is the most common form of sensory impairment in humans and is frequently caused by single gene mutations. Interestingly, different mutations in a gene can cause syndromic and nonsyndromic forms of deafness, as well as progressive and age-related hearing loss. We provide here an explanation for the phenotypic variability associated with mutations in the cadherin 23 gene (CDH23). CDH23 null alleles cause deaf-blindness (Usher syndrome type 1D; USH1D), whereas missense mutations cause nonsyndromic deafness (DFNB12). In a forward genetic screen, we have identified salsa mice, which suffer from hearing loss due to a Cdh23 missense mutation modeling DFNB12. In contrast to waltzer mice, which carry a CDH23 null allele mimicking USH1D, hair cell development is unaffected in salsa mice. Instead, tip links, which are thought to gate mechanotransduction channels in hair cells, are progressively lost. Our findings suggest that DFNB12 belongs to a new class of disorder that is caused by defects in tip links. We propose that mutations in other genes that cause USH1 and nonsyndromic deafness may also have distinct effects on hair cell development and function.
Schwander
Martin
M
Department of Cell Biology and Institute of Childhood and Neglected Disease, The Scripps Research Institute, La Jolla, CA 92037, USA.
Xiong
Wei
W
Tokita
Joshua
J
Lelli
Andrea
A
Elledge
Heather M
HM
Kazmierczak
Piotr
P
Sczaniecka
Anna
A
Kolatkar
Anand
A
Wiltshire
Tim
T
Kuhn
Peter
P
Holt
Jeffrey R
JR
Kachar
Bechara
B
Tarantino
Lisa
L
Müller
Ulrich
U
D000818:Animals; D015820:Cadherins / Q000235:genetics*; D003638:Deafness / Q000235:genetics*; D004195:Disease Models, Animal; D006198:Hair Cells, Auditory; D040542:Mechanotransduction, Cellular / Q000235:genetics; D051379:Mice; D020125:Mutation, Missense; D052245:Usher Syndromes / Q000235:genetics
D015820:Cadherins; C499091:Cdh23 protein, mouse