Complex sentence: The most prominent of these, affecting the skeletal system, are found in numerous other diseases (see Differential Diagnosis, below), thus it is not possible to make a diagnosis of Marfan syndrome simply by the person's appearance.
Split into simpler sentences: The most prominent of these, affecting the skeletal system, are found in numerous other diseases (see Differential Diagnosis, below). Thus, it is not possible to make a diagnosis of Marfan syndrome simply by the person's appearance.