A girl with severe visual impairment was born in a family from a Moscow suburb. The parents were very concerned, consulted and observed her with specialists, the girl underwent several unsuccessful operations. When a second girl was born in the family with a similar eye lesion, as well as other features of her appearance, the hereditary nature of the disease became clear. The geneticist recommended genome analysis to all four family members. For young parents, this was financially impossible. They turned to a foundation that funded the research. The result confirmed the hereditary nature of the visual impairment: from each of the parents, the girls inherited one “breakdown” of the gene responsible for eye damage. However, the analysis also revealed that both parents are also asymptomatic carriers of another very serious illness (one of the storage diseases), which significantly impairs the patient's quality of life and life expectancy. The disease may not appear immediately at birth, but delayed. There is no effective treatment. Knowing this information is very important for planning your fertility.