Mutations in the myosin VIIA gene cause non-syndromic recessive deafness.
Genetic hearing impairment affects around 1 in every 2,000 births. The bulk (approximately 70%) of genetic deafness is non-syndromic, in which hearing impairment is not associated with any other abnormalities. Over 25 loci involved in non-syndromic deafness have been mapped and mutations in connexin 26 have been identified as a cause of non-sydromic deafness. One locus for non-syndromic recessive deafness, DFNB2 (ref. 4), has been localized to the same chromosomal region, 11q14, as one of the loci, USH1B, underlying the recessive deaf-blind syndrome. Usher syndrome type 1b, which is characterized by profound congenital sensorineural deafness, constant vestibular dysfunction and prepubertal onset of retinitis pigmentosa. Recently, it has been shown that a gene encoding an unconventional myosin, myosin VIIA, underlies the mouse recessive deafness mutation, shaker-1 (ref. 5) as well as Usher syndrome type 1b. Mice with shaker-1 demonstrate typical neuroepithelial defects manifested by hearing loss and vestibular dysfunction but no retinal pathology. Differences in retinal patterns of expression may account for the variance in phenotype between shaker-1 mice and Usher type 1 syndrome. Nevertheless, the expression of MYO7A in the neuroepithelium suggests that it should be considered a candidate for non-syndromic deafness in the human population. By screening families with non-syndromic deafness from China, we have identified two families carrying MYO7A mutations.
Liu
X Z
XZ
MRC Mouse Genome Centre, Harwell, Oxfordshire, UK.
Walsh
J
J
Mburu
P
P
Kendrick-Jones
J
J
Cope
M J
MJ
Steel
K P
KP
Brown
S D
SD
D000328:Adult; D000818:Animals; D002880:Chromosomes, Human, Pair 11; D003638:Deafness / Q000235:genetics*; D004398:Dyneins; D005091:Exons; D005808:Genes, Recessive; D006579:Heterozygote; D006801:Humans; D051379:Mice; D008875:Middle Aged; D009154:Mutation; D000081412:Myosin VIIa; D009218:Myosins / Q000235:genetics*; D010375:Pedigree; D012326:RNA Splicing
C000631455:MYO7A protein, human; C000631456:Myo7a protein, mouse; D000081412:Myosin VIIa; D009218:Myosins; D004398:Dyneins