Scientists at the National Eye Institute (NEI) have developed a promising gene therapy strategy for a rare disease that causes severe vision loss in childhood. A form of Leber congenital amaurosis, the disease is caused by autosomal-dominant mutations in the CRX gene, which are challenging to treat with gene therapy. The scientists tested their approach using lab-made retinal tissues built from patient cells, called retinal organoids. This approach, which involved adding copies of the normal gene under its native control mechanism, partially restored CRX function. The study report appears today in Stem Cell Reports. NEI is part of the National Institutes of Health.