Actually, there is an EXCELLENT book on hemophilia and the royal family-Queen Victoria’s Gene: Hemophilia and the Royal Family, by the Potts brothers.
Also, what about the youngest child of George V and Queen Mary, little Prince John? At the age of four, he had developed severe epilepsy, and when he was about…oooh, maybe 10? they had him sent to a separate residence with a nurse and he wasn’t seen in public. The ONLY royal who visited him was his grandmother, the Dowager Queen Alexandra, who doted on little John and called him her sweet, dear little boy. She adored him and visited him frequently. John I believe died during a seizure when when he was 13. Alexandra was crushed and very depressed upon his death. She was the chief mourner at his funeral. I know his parents mentioned him little, although from what I understand, Queen Mary was very upset and very mournful at his death.
Insane Tsars? Or Tsars who had mental health issues or what have you? Well, there was the Tsar Ivan V, Peter the Great’s brother and co-Tsar, who probably suffered from Downs Syndrome. Ivan’s eventual descendent, the baby Tsar, Ivan VI, who only reigned for a year as an infant and then was locked away became mentally ill. Catherine’s son Paul was paranoid, and his son Alexander I suffered from depression, as did many, many many royals. Hell, Peter the Great was almost crazy!
Poryphoria also haunted the Hohenzollerns, the Kaiser Wilhelm II’s sister Charlotte, and their ancestor, Frederick the Great. Frederick Wilhelm IV, Willy’s great-uncle had mental problems. The Wittelsbachs of Bavaria, including Ludwig II-Mad King Ludwig, and Empress Elisabeth of Austria-Hungary were mentally ill. Crown Prince Rudolf committed the famous murder suicide at Mayerling.