Great lecture! I am an senior exposure-disease causation reviewer following applicable causation determination approaches such as the well-known Bradford-Hill causation criteria. My work focus on medical-scientific-legal evidence. I am now evaluating the differentiation evidence between Post-Polio and FSHD causations. My question is how we can differentiate between Post-Polio Syndrome and FSHD without D4Z4 test? Thanks, Jianping Cui, MB MSc CIH Toronto ON M2N 7L4 Canada