CRISPR/Cas9-Mediated Gene Correction in Newborn Rabbits with Hereditary Tyrosinemia Type I

Area of Science:

• Genetics
• Molecular Biology
• Gene Therapy

Background:

• Hereditary tyrosinemia type I (HT1) causes severe liver and kidney damage in infants.
• Current treatments are insufficient, and rodent models do not fully represent human disease.
• Large animal models are essential for validating gene therapy before clinical application.

Purpose of the Study:

• To evaluate the efficacy and safety of CRISPR-Cas9 gene therapy in a large animal model of HT1.
• To assess the potential of adeno-associated virus (AAV) delivery for precise gene correction in vivo.
• To establish preclinical data for treating hepatocyte-related metabolic disorders.

Main Methods:

• Newborn HT1 rabbits received CRISPR-Cas9 and donor templates via AAV.
• Gene correction efficiency was assessed using homology-directed repair (HDR) and non-homologous end joining (NHEJ).
• Liver and kidney structures, functions, and animal survival were monitored.

Main Results:

• AAV-mediated gene therapy rescued lethal HT1 phenotypes in rabbits.
• Treated rabbits survived to adulthood, reproduced, and showed normal liver and kidney function.
• HDR and NHEJ-mediated gene correction efficiencies ranged from 0.90%–3.71% and 2.39%–6.35% respectively, sufficient for functional recovery.

Conclusions:

• CRISPR-Cas9 gene therapy delivered via AAV is a viable strategy for treating HT1 in a large animal model.
• This approach demonstrates potential for rescuing monogenetic metabolic disorders affecting the liver.
• The study provides critical preclinical evidence for advancing precise gene therapy to clinical trials.