Conclusion: The results of this study support the assertion that Southern European individuals have a genetically mediated predisposition to develop idiopathic sudden sensorineural hearing loss (SNHL).
Objective: To assess the influence of human leukocyte antigen (HLA)-DQB1 and -DRB1 alleles on the susceptibility to and the severity of idiopathic sudden SNHL.
Material and methods: A prospective study of patients diagnosed with idiopathic sudden SNHL between October 2000 and September 2002 was conducted. Patients were included in the study if they were diagnosed with idiopathic sudden SNHL within 1 week after the onset of deafness symptoms and had been followed for at least 12 months. HLA-DQB1 and -DRB1 typing was performed from DNA using molecular-based methods on patients and ethnically matched healthy controls.
Results: Thirty-three patients fulfilled the inclusion criteria. No significant differences in HLA-DQB1 phenotype frequencies were found between patients and controls (n = 145). Carriage of HLA-DRB1*0403 was significantly increased in the whole group of patients compared with controls (OR = 11.97; 95% CI 1.99-91.60; p = 0.002; p(corr) = 0.04). In patients without auditory improvement the frequency of the HLA-DRB1*04 phenotype was significantly increased compared with healthy controls (OR = 6.57; 95% CI 1.62-26.70; p = 0.003; p(corr) = 0.04).