<prompt> The otopathology in the case of Alpo syndrome is:Defect in the cochlear basement membranesDefect in conductionDefect in the vestibulocochlear nerveNone of the above  <response>: The otopathology in AS is a defect in the cochlear basement membranes. Type IV collagen chains in the active tuning of the basilar and tectorial membrane which is an essential step in frequency discrimination and amplification of auditory signals are affected. Ref: Dan Med Bull 2009; 56:105-52 