The retinal phenotype of Usher syndrome: pathophysiological insights from animal models.
The Usher syndrome (USH) is the most prevalent cause of inherited deaf-blindness. Three clinical subtypes, USH1-3, have been defined, and ten USH genes identified. The hearing impairment due to USH gene defects has been shown to result from improper organisation of the hair bundle, the sound receptive structure of sensory hair cells. In contrast, the cellular basis of the visual defect is less well understood as this phenotype is absent in almost all the USH mouse models that faithfully mimic the human hearing impairment. Structural and molecular interspecies discrepancies regarding photoreceptor calyceal processes and the association with the distribution of USH1 proteins have recently been unravelled, and have led to the conclusion that a defect in the USH1 protein complex-mediated connection between the photoreceptor outer segment and the surrounding calyceal processes (in both rods and cones), and the inner segment (in rods only), probably causes the USH1 retinal dystrophy in humans.
Institut Pasteur, unité de génétique et physiologie de l'audition, 25, rue du Docteur-Roux, 75015 Paris, France; Inserm UMRS1120, 75015 Paris, France; UPMC, 75015 Paris, France. Electronic address: aziz.el-amraoui@pasteur.fr.
Aziz
A
El-Amraoui
Institut Pasteur, unité de génétique et physiologie de l'audition, 25, rue du Docteur-Roux, 75015 Paris, France; Inserm UMRS1120, 75015 Paris, France; UPMC, 75015 Paris, France; Collège de France, 75005 Paris, France. Electronic address: christine.petit@pasteur.fr.
Christine
C
Petit
D000818:Animals; D004195:Disease Models, Animal; D000882:Haplorhini; D006311:Hearing Disorders / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D051379:Mice; D010641:Phenotype; D012160:Retina / Q000473:pathology* / Q000503:physiopathology*; D052245:Usher Syndromes / Q000473:pathology* / Q000503:physiopathology*; D014786:Vision Disorders / Q000209:etiology / Q000503:physiopathology
Calyceal processes; Cellule ciliée auditive; Deafness; Hair bundle; Hair cell; Photoreceptor cell; Photorécepteurs; Processus caliciels; Retinitis pigmentosa; Rétinite pigmentaire; Surdité; Syndrome de Usher; Touffe ciliaire; Usher syndrome