HGSNAT and Abnormal retinal morphology: In 2015, three families with specific HGSNAT genotypes were first associated with isolated late‐onset slowly progressive retinal disease (Haer‐Wigman et al., 2015) and this was followed by several reports, each of a few additional families (Carss et al., 2017; Comander et al., 2017; Long et al., 2020; Van Cauwenbergh et al., 2017).