Vitelliform macular dystrophy (VMD) and retinitis pigmentosa (RP) are major causes of inherited visual impairment. Mutations in the IMPG1 gene have previously been described in patients with VMD. In the present study, we describe seven variants in IMPG1 in 11 families and provide two additional IMPG1-associated diagnoses: autosomal dominant and autosomal recessive RP. IMPG1 encodes the SPACR protein, a component of the rod and cone photoreceptor extracellular matrix domains. In addition, we describe the functional analysis of the medaka fish ortholog of the human IMPG1 gene which indicates that SPACR plays an important role both in early retinal development and during later retinal maintenance. (By Dr. Gaël Manes, https://jmg.bmj.com/content/early/2020/08/17/jmedgenet-2020-107150 )