Usher Syndrome, Type IF (PCDH15)
Usher syndrome type 1F is an autosomal recessive disease caused by pathogenic variants in the gene PCDH15. While it is a pan-ethnic disease, due to the presence of a founder mutation it is particularly prevalent in people of Ashkenazi Jewish ancestry. The disease is characterized by congenital bilateral sensorineural deafness, which may be treated by cochlear implants; hearing aids do not help. Progressive loss of vision due to retinitis pigmentosa begins in childhood. Retinitis pigmentosa first presents with night blindness, but progresses to tunnel vision and eventually blindness. Patients also have problems with their balance and therefore experience developmental delay. Some patients with missense variants, rather than null variants, may manifest only with deafness. Life expectancy is not reduced.
For information about carrier frequency and residual risk, please see the residual risk table.