TFF2 and Huntington disease: Thus, it is uncertain if the dystonic phenotype in these mice is attributable to loss of SP+ striatal neurons, or whether loss of cortical D1 neurons accounts for the phenotype.71 In any event, the present findings show that PARV+ striatal interneuron loss is prominent in HD, and available animal data on basal ganglia function are consistent with the view that this loss in motor striatum might contribute to dystonic symptoms.