Usher syndrome type II

Abstract

Introcuction: Usher syndrome is a disease with an autosomal recessive inheritance that associates sensorineural hearing loss, retinitis pigmentosa and vestibular dysfunction in some cases. It has an estimated prevalence in the world of 3.8-4.4 / 100,000 inhabitants, constituting the most common association of hearing loss and blindness of genetic origin. Clinically Usher syndrome is divided into three types, according to the severity of hearing loss, age of onset of retinosis pigmentosa and the existence or not of vestibular dysfunction. Clinical case: We reported a 47-year-old male referred to our department for hearing evaluation. The patient has had a visual alteration for years and recently he has being diagnosed with retinitis pigmentosa, with a genetic study in which variant of unknown significance has been detected in the USH2A gene. The patient has not noticed hearing loss and does not report dizzying symptoms. Both physical and otoneurological examination is normal. In the audiometry performed we observed a moderate, bilateral, sensorineural hearing loss. The magnetic resonance performed was normal. The patient will adapt auditory prosthesis in both ears. Discussion: Usher syndrome type II (USH2) usually presents with a milder hearing loss, without vestibular involvement and with an appearance of retinitis pigmentosa later than in type I. 85% of USH2 cases present mutations in the Usherin gene (USH2A). The 2299delG mutation is the most frequent mutation in patients with USH2 in the world and its frequency is estimated at 25% in the Spanish population. So far, no curative treatment for Usher syndrome has been discovered. Current treatments try to improve the hearing loss or retinal degeneration. Cochlear implantation is a good alternative for children, if it is performed at an early age.