A defect in harmonin, a PDZ domain-containing protein expressed in the inner ear sensory hair cells, underlies Usher syndrome type 1C.
Usher syndrome type 1 (USH1) is an autosomal recessive sensory defect involving congenital profound sensorineural deafness, vestibular dysfunction and blindness (due to progressive retinitis pigmentosa)1. Six different USH1 loci have been reported. So far, only MYO7A (USH1B), encoding myosin VIIA, has been identified as a gene whose mutation causes the disease. Here, we report a gene underlying USH1C (MIM 276904), a USH1 subtype described in a population of Acadian descendants from Louisiana and in a Lebanese family. We identified this gene (USH1C), encoding a PDZ-domain-containing protein, harmonin, in a subtracted mouse cDNA library derived from inner ear sensory areas. In patients we found a splice-site mutation, a frameshift mutation and the expansion of an intronic variable number of tandem repeat (VNTR). We showed that, in the mouse inner ear, only the sensory hair cells express harmonin. The inner ear Ush1c transcripts predicted several harmonin isoforms, some containing an additional coiled-coil domain and a proline- and serine-rich region. As several of these transcripts were absent from the eye, we propose that USH1C also underlies the DFNB18 form of isolated deafness.
Verpy
E
E
Unité de Génétique des Déficits Sensoriels, CNRS URA 1968, Institut Pasteur, Paris cedex 15, France.
Leibovici
M
M
Zwaenepoel
I
I
Liu
X Z
XZ
Gal
A
A
Salem
N
N
Mansour
A
A
Blanchard
S
S
Kobayashi
I
I
Keats
B J
BJ
Slim
R
R
Petit
C
C
D048868:Adaptor Proteins, Signal Transducing; D000483:Alleles; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000378:metabolism; D005091:Exons; D005192:Family Health; D016368:Frameshift Mutation; D017353:Gene Deletion; D015723:Gene Library; D006199:Hair Cells, Auditory, Inner / Q000378:metabolism / Q000473:pathology*; D018069:Hair Cells, Vestibular / Q000378:metabolism; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D007150:Immunohistochemistry; D007438:Introns; D051379:Mice; D018598:Minisatellite Repeats / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010375:Pedigree; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D012326:RNA Splicing / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D012162:Retinal Degeneration / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D014018:Tissue Distribution; D014158:Transcription, Genetic
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D020033:Protein Isoforms; D012333:RNA, Messenger; C118970:USH1C protein, human; C492262:Ush1c protein, mouse