MacGregor’s Syndrome is a fictional disease that afflicted Nora Fries, the wife of Batman villain Mr. Freeze in Batman and Robin before being drafted in by Arrow as a terminal illness suffered by the Clock King, William Tockman, in season two.
Batman revealed that Nora had the most advanced stages of this disease, for which Mr. Freeze has yet to find a cure, although he managed to cure the first few stages of the disease.
The same illness struck Francine West, the estranged wife of Joe West in the TV series The Flash.
Of interest, check out these 10 Fictional Diseases (and the Real Ones That Inspired Them), shared by Inverse.com.