Canadian researchers announce the discovery of MEDNIK, a debilitating genetic syndrome, in a study published December 5 in the open-access journal PLoS Genetics.  The team demonstrates that this syndrome is caused by a newly found mutation in the human AP1S1 gene. Dr. Patrick Cossette and his team discovered MEDNIK syndrome in a group of families in Quebec that share a common ancestor.  The syndrome is characterized by mental retardation, enteropathy, deafness, peripheral neuropathy, ichthyosis, and keratodermia (MEDNIK).