Auditory neuropathy spectrum disorder (ANSD) is a type of hearing loss in which transmission of auditory signals from the inner ear to the brain stem is distorted, giving rise to speech perception difficulties beyond that expected for the observed degree of hearing loss. Although its prevalence is high – ANSD has an incidence of 13% in children with severe-to-profound hearing loss – in many cases, the molecular pathology remains unclear. Underlying etiologies include toxic/metabolic derangements, infections, immunological causes, drugs and genetic abnormalities, with 40% of ANSD having a genetic basis. We now implicate mutation of AIFM1 as a common cause of familial and sporadic ANSD in male, often occured at adolescence. Our finding of cochlear nerve hypoplasia in some patients implies that magnetic resonance imaging may be of value in localizing the site of lesion and suggests that cochlea implantation in these patients may be chosen carefully. (By Dr. Qiuju Wang , http://jmg.bmj.com/content/early/2015/05/17/jmedgenet-2014-102961 )
