Characterization of a novel conditional knockout mouse model to assess efficacy of mRNA therapy in the context of severe ornithine transcarbamylase deficiency.

Ornithine transcarbamylase deficiency (OTCD) is the most common urea cycle disorder, characterized by hyperammonemia and accompanied by a high unmet patient need. mRNA therapies have been shown to be efficacious in hypomorphic Sparse-fur abnormal skin and hair (Spf-ash) mice, a model of late-onset disease. However, studying the efficacy of ornithine transcarbamylase (OTC) mRNA therapy in traditional knockout mice, a model for severe early-onset OTCD, is hampered by the rapid lethality of the model, and poor lipid nanoparticle (LNP) uptake into neonatal mouse liver.

Whole-body galactose oxidation as a robust functional assay to assess the efficacy of gene-based therapies in a mouse model of Galactosemia.

Despite the implementation of lifesaving newborn screening programs and a galactose-restricted diet, many patients with classic galactosemia develop long-term debilitating neurological deficits and primary ovarian insufficiency. Previously, we showed that the administration of human mRNA predominantly expressed in the gene-trapped mouse liver augmented the expression of hepatic GALT activity, which decreased not only galactose-1 phosphate (gal-1P) in the liver but also peripheral tissues. Since each peripheral tissue requires distinct methods to examine the biomarker and/or GALT effect, this highlights the necessity for alternative strategies to evaluate the overall impact of therapies.