<prompt> MEDNIK syndrome - which of the following is trueCaused by mutations in the AP1S1 geneDisorder of copper metabolismMental retardation, deafness, neuropathy are seen in this disorderAll of the above  <response>: A rare multisystem disorder of copper metabolism with features of both Menkes and Wilsons diseases has been repoed. It is termed the MEDNIK mental retardation, enteropathy, deafness, neuropathy, ichthyosis, keratodermia syndrome and is caused by mutations in the AP1S1 gene, which encodes an adaptor protein necessary for intracellular trafficking of copper pump proteins ATP7A Menkes disease and ATP7B Wilsons disease. 