Inherited diseases Faulty genes can cause rare diseases such as immunodeficiency, haemophilia and lysosomal storage disease. Gene therapy can potentially cure patients with these conditions. Haemophilia Inherited bleeding disorders are conditions in which the blood does not clot properly. Immunodeficiency Primary immunodeficiency disorders are caused by inherited genetic defects. Lysosomal storage disease Mutations of lysosomes can cause problems with the enzymes and how they work.