Systemic gene therapy corrects neurological phenotype in a mouse model of NGLY1 deficiency

The cytoplasmic peptide:N-glycanase (NGLY1) is ubiquitously expressed and functions as a de-N-glycosylating enzyme that degrades misfolded N-glycosylated proteins. NGLY1 deficiency due to biallelic loss-of-function NGLY1 variants is an ultrarare autosomal recessive deglycosylation disorder with multisystemic involvement; the neurological manifestations represent the major disease burden. Currently, there is no treatment for this disease. To develop a gene therapy, we first characterized a tamoxifen-inducible Ngly1 knock-out (iNgly1) C57BL/6J mouse model, which exhibited symptoms recapitulating human disease, including elevation of the biomarker GlcNAc-Asn (GNA), motor deficits, kyphosis, Purkinje cell loss, and gait abnormalities.