Neuronal intranuclear inclusion disease: Polyglycine protein is the culprit

In this issue of Neuron, Boivin et al. (2021) show that a polyglycine-expanded protein, uN2CpolyG, is translated from an expansion of GGC repeats in the 5′ UTR of the NOTCH2NLC (Notch homolog 2 N-terminal-like C) gene, defining a new pathological mechanism for neuronal intranuclear inclusion diseases (NIID).