HIP1 and Failure to thrive: Huntington-interacting-protein-1 colocalizes in hippocampal and cortical neurons with N-methyl-D-aspartate (NMDA) and a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, and modulates their trafficking.1,17,18 NMDA and AMPA receptors play important roles in synaptic plasticity and excitotoxic cell death.17 Mouse models with targeted null mutation in the HIP1 gene developed abnormal AMPA receptor trafficking and an abnormal neurological phenotype including epilepsy and failure to thrive.1,18