My posts were moved here
I posted these replies elsewhere, and they must have been moved here. Very efficient! I am new on this forum so have not been finding my way efficiently around the forum.
Red urine is not always found in porphyria, nor even purple. It was a strong feature of James I/VI, one reason for fairly easy diagnosis of him, even though he lived before we had the modern "tests". But porphyria is generally dx'd as much from family history and ruling out other causes as it is from tests, as the tests are not very good and not very well done except under the best of circumstances.
As for the earlier Gloucester heir, I had not read that he had not succeeded to the title when he was killed. He was dx'd by an English doctor at the behest of his mother, who noticed lesions on his face, a feature of some kinds, but not of all, porphyria. Then he was re-diagnosed in South America where he was a business representative. The fact that his brother married a non-royal, and their children have married non-royals, offers hope that this family will escape the disease, which is "dominant", and affects 50% of children...but maybe the present Duke of Gloucester was one of the blessed 50% who did not get it--and in that case, it is dead as a doornail... it is not recessive in the type this family has had, although there is a rare form of porphyria which is recessive.
The disease affected the royals before the Hanover arrival. As I said, James I/VI is thought to have gotten it from Mary Queen of Scots and/or Lord Darnley. Lord Darnley had not only the Stewart genes but also the Tudor genes, and the Tudors, in my opinion, became active with porphyria through Katherine of Valois, who married first Henry V and then Owen Tudor. Katherine is not written up as "mad", but her father Charles VI of France was actually more often "mad" than George III. He did terrible things such as kill his aides, and then fall into sorrow over what he'd done when he recovered his right mind. He thought he was made of glass and could break. He came from a very inbred line, and his wife Isabeau may have had it as well...thus Katherine had a very high chance of having it. However, in these old cases, there are no "lab tests" as there are now since the 20th century.
My type of porphyria, HCP, is not the same as the Hanover type dx'd through DNA on the bones of Vicki and Charlotte, Queen V's child and grandchild. They had VP. Both types do involve skin lesions, so I am well covered when outside and have tinted windows. I have wondered if somehow I got HCP from the Stuarts, since my ancestor Robert de Pollock came from a Jacobite family in the 11th and 12th centuries in Brittany, England (shropshire) and Scotland (Renfrewshire). Robert de Pollock had land adjacent to that of Walter Fitzallen and contributed to the same monasteries that Walter did (Paisley and Melrose). there are Stuart marriages in the lineage of Robert de Pollock, but I have no knowledge of a direct line to me. In limbo.