MFF and Huntington disease: To address the effect of Mff on HD pathology, we designed a mating schemeto generate HDR6/2 mice lacking Mff. Ina previous study15, we engineered a mouseline (Mffgt/gt) containing a gene trap insertion withinthe Mff locus that constitutively eliminates expression of all Mffprotein isoforms, results in secondary reduction of Drp1 levels, and causes a severemitochondrial fission defect.