Concept:A disease transmittable through genes is a hereditary condition caused by an abnormal gene passed from parents to offspring.Explanation:HIV/AIDS is caused by a virus. It is an infectious disease, not inherited through genes.Sickle cell anaemia is caused by a defective gene that is inherited. A child receives this gene from one or both parents.Diabetes can result from lifestyle, diet, or other factors. It is not strictly a gene-transmitted disease.Presbyopia is an age-related eye condition. It is not caused by inherited genetic changes.Only sickle cell anaemia is directly transmittable through genes.Answer:Sickle cell anaemia