HTT and juvenile Huntington disease: To evaluate an in vivo role of iRhom1 in the clearance of mtHtt, we established iRhom-knockout (KO1), Drosophila iRhom [UAS-iRhom1 (dr)]- or human iRhom1 [UAS-iRhom1 (h)]-overexpressing flies, and crossed them with Htt-Q128 flies, which express Htt-Q128, display the rough-eye phenotype, and represent a Huntington disease model30.