syn·drome- A group of symptoms that consistently occur together or a condition characterized by a set of associated symptoms.Dis·ease A disorder of structure or function in a human, animal, or plant, especially one that produces specific signs or symptoms or that affects a specific location and is not simply a direct result of physical injury.
This is an excellent question!!! And hard to explain but I am going to try (no guarantees): a syndrome is a disease with the same symptoms. For instance, cancer is a disease but there are a lot of different symptoms (due to the different origins of the tumor). Lynch syndrome is a disease where there is a genetic mutation (symptom) causing causing tumors in predominantly the colon and uterus. Mental retardation (disease) has different causes, Down syndrome is a genetic mutation causing mental retardation. Hopefully I have made it a little clearer 😕