The deletion of Lsd1 could result in: (1) Retinal degeneration due to retinal progenitor cells being unable to proliferate and/or cells undergoing cell death due to aberrant epigenomic regulation; or (2) Improper differentiation of retinal progenitor cells into mature retinal neurons leading to an over- or under-representation of certain neuronal populations, specifically photoreceptors. The gene discussed is KDM1A; the disease is retinal degeneration.