Skip to content Skip to navigation

Gene Therapy Lab

Gene therapy can modify mutations in genes or deliver an extra, healthy copy of an allele to treat inherited forms of blindness. Dr. Mahajan was a surgeon in the recent trial for gene therapy using a viral vector that successfully rescued vision loss in patients with Leber Congenital Amaurosis. The development of pre-clinical models to test gene therapy approaches for other forms of blindness, as well as testing gene therapy treatments in these pre-clinical animal models, is necessary and important to lead to clinical trials for human patients.

We are treating human patient stem cells and translational animal models with gene therapy approaches. We are also developing animal models for various inherited retinal degenerative diseases by introducing human genes or human mutations into the animals.

Pluripotent stem cells are made in the lab from patient volunteers with retinal degenerations. We then use gene editing (CRISPR) to correct the patient mutations in their own cells. Our lab was the first to correct a human blindness gene in human stem cells. These gene-corrected cells can then be used to test therapies and create transplants that replace diseased retinas.


Fixing faulty genes.
Direct modification of DNA in living cells.
Gene therapy correction in pre-clinical models of retinal disease.


Dec 14 2018 | Posted In: 20/20 Blog
Palo Alto, CA — Why volunteer for a clinical trial? The rigorous process of turning a new therapy into the standard of care depends on patient volunteers. 
Oct 27 2018 | Posted In: 20/20 Blog
Chicago, IL — At the American Academy of Ophthalmology meeting, Stanford ophthalmologist, Vinit Mahajan M.D., Ph.D., presented a poster detailing results on the relationship between specific patient mutations and clinical outcomes in the first FDA approved gene therapy trial in humans.
Sep 19 2018 | Posted In: 20/20 Blog
Dayton, OH — In the fall, Trisha Kulkarni will join the Stanford University freshman class and will no longer have to get on a plane to see Dr. Mahajan for eye exams, but that doesn’t mean she won’t be flying high. With Trisha, the sky is the limit. 
Jul 31 2018 | Posted In: 20/20 Blog
Park City, UT — Every summer for the past sixty-one years, the American Eye Study Club (AESC) has brought together ophthalmologists from across the country to share their expertise.
Jul 12 2018 | Posted In: 20/20 Blog
Palo Alto, CA — Dr. Vinit Mahajan and Dr.


Unexpected mutations after CRISPR-Cas9 editing in vivo, Schaefer, Kellie A., Wu Wen-Hsuan, Colgan Diana F., Tsang Stephen H., Bassuk Alexander G., and Mahajan Vinit B. , Nature methods, Volume 14, Number 6, p.547–548, (2017)
Structural modeling of a novel SLC38A8 mutation that causes foveal hypoplasia, Toral, Marcus A., Velez Gabriel, Boudreault Katherine, Schaefer Kellie A., Xu Yu, Saffra Norman, Bassuk Alexander G., Tsang Stephen H., and Mahajan Vinit B. , Molecular genetics & genomic medicine, Volume 5, p.202–209, (2017)
Electroretinography Reveals Difference in Cone Function between Syndromic and Nonsyndromic USH2A Patients, Sengillo, Jesse D., Cabral Thiago, Schuerch Kaspar, Duong Jimmy, Lee Winston, Boudreault Katherine, Xu Yu, Justus Sally, Sparrow Janet R., Mahajan Vinit B., et al. , Scientific reports, Volume 7, Number 1, p.11170, (2017)
Gene Therapy Restores Mfrp and Corrects Axial Eye Length, Velez, Gabriel, Tsang Stephen H., Tsai Yi-Ting, Hsu Chun-Wei, Gore Anuradha, Abdelhakim Aliaa H., Mahajan Maryann, Silverman Ronald H., Sparrow Janet R., Bassuk Alexander G., et al. , Scientific reports, Volume 7, p.16151, (2017)
Precision medicine: genetic repair of retinitis pigmentosa in patient-derived stem cells, Bassuk, Alexander G., Zheng Andrew, Li Yao, Tsang Stephen H., and Mahajan Vinit B. , Scientific reports, Volume 6, p.19969, (2016)
CAPN5 mutation in hereditary uveitis: the R243L mutation increases calpain catalytic activity and triggers intraocular inflammation in a mouse model, Wert, Katherine J., Bassuk Alexander G., Wu Wen-Hsuan, Gakhar Lokesh, Coglan Diana, Mahajan Maryann, Wu Shu, Yang Jing, Lin Chyuan-Sheng, Tsang Stephen H., et al. , Human molecular genetics, Volume 24, Number 16, p.4584–4598, (2015)