The purple secret.

Documentary tracing the inherited disease Variegate Porphyria through the royal family from King George III to Prince William of Gloucester. George III's symptoms are compared with those of present day Porphyria sufferer Stephanie Woods which typically include severe abdominal pains, dark urine and bursts of madness. Queen Victoria, grand-daughter of George III, is believed to have passed the disease on to her eldest daughter Vicky whose daughter Charlotta also appeared to have the classic symptoms. DNA taken from Charlotta's remains showed a mutant strain of Variegate Porphyria that matched with that taken from Princess Feodora, a cousin of Queen Elizabeth II. Feodora committed suicide in Poland in 1945 due to the unbearable pain of her illness. Further research discovered the fact that Prince William of Gloucester (1941-1972) also suffered from Porphyria. The programme ends by wondering if any other members of the royal family today are carrying the disease.