Mitochondrial haplogroup B increases the risk for hearing loss among the Eastern Asian pedigrees carrying 12S rRNA 1555A〉G mutation

Dear Editor, Hearing loss is one of the major public health problems. The mitochondrial DNA mutations has been found to be associ- ated with both aminoglycoside-induced and nonsyndromic hearing loss （FischeI-Ghodsian, 1999; Guan, 2011）. The 1555A〉G mutation in mitochondrial small subunit ribosomal RNA （rRNA） gene contributes to nonsyndromic hearing loss and is prevalent in Asian and other populations （Guan, 2011）. This mutation was first identified in families with aminogly- coside-induced deafness, and the ototoxic susceptibility was attributed to enhanced binding affinity to aminoglycosides of 1555A〉G rRNA （Qian and Guan, 2009）. In the absence of aminoglycoside antibiotics, individuals with 1555A〉G mutation exhibit various clinical phenotype that ranges from severe congenital deafness, through moderate progressive hearing loss of late onset,