Disease relevance of Clrn1

• While most MYO7A mutations cause USH1, some cause nonsyndromic hearing impairment, and one USH3 phenotype has been described [1].
• USH3 is characterized by progressive hearing loss and variable age of onset of retinal degeneration [1].
• Usher syndrome type III: revised genomic structure of the USH3 gene and identification of novel mutations [2].

High impact information on Clrn1

• Expression of Ush3a transcripts was localised by whole mount in situ hybridisation to cochlear hair cells and spiral ganglion cells [3].
• Usher syndrome type 3 (USH3) is an autosomal recessive disorder characterised by the association of post-lingual progressive hearing loss, progressive visual loss due to retinitis pigmentosa and variable presence of vestibular dysfunction [3].
• Limited sequence homology to stargazin, a cerebellar synapse four-transmembrane-domain protein, suggests a role for clarin-1 in hair cell and photoreceptor cell synapses, as well as a common pathophysiological pathway for different Usher syndromes [3].
• By analysis of linkage disequilibrium and historical recombinations in 77 USH3 chromosomes, the location of the Finnish USH3 mutation could be narrowed to an approximately 1-cM interval between the markers D3S1299 and D3S3625 [4].

References