In this study, we present the ophthalmologic findings observed in both the human patient carrying HBS1L recessive variants and Hbs1ltm1a/tm1a mice, demonstrating that Hbs1l deficiency triggers extensive apoptosis of photoreceptor cells as early as postnatal day (P) 14 in mice and subsequent retinal degeneration. The gene discussed is HBS1L; the disease is retinal degeneration.