Revision about hearing loss in the Alport's syndrome, analyzing the clinical, genetic and bio-molecular aspects.
Alport Syndrome is a genetic disorder characterized by hematuria, which often leads to renal failure. It may also be accompanied by extra-renal alterations, such as: sensorineural hearing loss, and ocular abnormalities. Dominant forms related to the X chromosome and caused by mutations in the locus COL4A5 have been described, as well as an autossomic recessive form resulting from mutations in the locus COL4A3 or COL4A4. An autossomic dominant type of AS has also been reported. The disease is caused by changes in the collagen type IV chains, where symptoms reflect the damage to the basal membrane of several organs. The alpha3.alpha4.alpha5(IV) networks are found in the kidneys, cochlea and eyes. The objective was to characterize AS in this group of patients. In the current literature review it was found that: 1. AS is characterized by hematuria that may develop into renal failure and can also be accompanied by extra-renal manifestations. Hearing loss is a frequent extra-renal finding and one of the first symptoms of AS, therefore representing a relevant factor in the prognosis of the renal disease; 2. It is a genetic disorder resulting from abnormalities in the chains of collagen type IV in the basal membranes; 3. The hearing loss in AS is typically sensorineural with variable intensities, progressive and symmetrical, affecting middle and high frequencies; 4. Otolaryngologists should include a urine test in the SNHL work-up. It is essential to have an otologist involved in the treatment of these patients.
Alves
Fátima R A
FR
Clínica de Otorrinolaringologia, Hospital do Servidor Público Municipal, Faculdade de Ciências Médicas, Santa Casa de São Paulo. ffraa@aol.com
de A Quintanilha Ribeiro
Fernando
F
D000818:Animals; D001299:Audiometry; D001485:Basement Membrane; D015415:Biomarkers; D024141:Collagen Type IV / Q000235:genetics*; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology / Q000235:genetics; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D009394:Nephritis, Hereditary / Q000150:complications / Q000175:diagnosis / Q000235:genetics
D015415:Biomarkers; D024141:Collagen Type IV