Long-term functional correction of cystathionine β-synthase deficiency in mice by adeno-associated viral gene therapy.

Publication Type	Academic Article
Authors	Lee H, Salami C, Sondhi D, Kaminsky S, Crystal R, Kruger W
Journal	J Inherit Metab Dis
Volume	44
Issue	6
Pagination	1382-1392
Date Published	10/11/2021
ISSN	1573-2665
Keywords	Cystathionine beta-Synthase, Dependovirus, Genetic Therapy, Genetic Vectors, Homocystinuria
Abstract	Cystathionine β-synthase (CBS) deficiency is a recessive inborn error of sulfur metabolism characterized by elevated blood levels of total homocysteine (tHcy). Patients diagnosed with CBS deficiency are currently treated by a combination of vitamin supplementation and restriction of foods containing the homocysteine precursor methionine, but the effectiveness of this therapy is limited due to poor compliance. A mouse model for CBS deficiency (Tg-I278T Cbs-/- ) was used to evaluate a potential gene therapy approach to treat CBS deficiency utilizing an AAVrh.10-based vector containing the human CBS cDNA downstream of the constitutive, strong CAG promoter (AAVrh.10hCBS). Mice were administered a single dose of virus and followed for up to 1 year. The data demonstrated a dose-dependent increase in liver CBS activity and a dose-dependent decrease in serum tHcy. Liver CBS enzyme activity at 1 year was similar to Cbs+/- control mice. Mice given the highest dose (5.6 × 1011 genomes/mouse) had mean serum tHcy decrease of 97% 1 week after injection and an 81% reduction 1 year after injection. Treated mice had either full- or substantial correction of alopecia, bone loss, and fat mass phenotypes associated with Cbs deficiency in mice. Our findings show that AAVrh.10-based gene therapy is highly effective in treating CBS deficiency in mice and supports additional pre-clinical testing for eventual use human trials.
DOI	10.1002/jimd.12437
PubMed ID	34528713
PubMed Central ID	PMC8578459