Role of genetic and acquired prothrombotic risk factors in genesis of sudden sensorineural hearing loss.

The methylenetetrahydrofolate reductase C677T mutation, factor V G1691A (factor V Leiden) mutation, prothrombin G20210A mutation and 8 other laboratory values associated with increased thrombotic risk were analyzed in 40 patients with sudden sensorineural hearing loss (SSHL). The results were compared with those obtained from 120 controls not affected by SSHL. We found a statistically significant higher frequency of hyperhomocysteinemia in the SSHL group compared with controls, and that this was also associated with the presence of homozygosity for the MTHFR C677T mutation. The study results suggest that SSHL might be caused, among other factors, by a combination of these 2 variables. We suggest that this analysis of the MTHFR C677T mutation should be further investigated to establish the etiology of SSHL, and that the same analysis should be taken into account in those patients with high levels of homocysteine.