Symptoms of the fatal single-gene disease answer include involuntary movements, mood swings, depression, irritability, and inability to remember facts.

The answer would be Huntington's disease.

Huntington's disease is a genetically inherited disease that was caused by a defect that will be inherited in autosomal dominant ways. That mean the children of the offspring to inherit the gene would be at least 50%. The symptoms would be personality disorder(mood swing, depression), decreased cognitive ability(forgetful), involuntary movement and unstable gait, slurred speech with difficulty in swallowing food. 

Tbh i think it’s an odd coincidence, maybe you “predicted the future” it’s happened to me before but i wouldn’t doubt it if you did but i hope you have fun

Yes violent video games can increase the risk of the person wanting to try out the things in reality , in real life . the person may be mad and want revenge and is playing the video game and the video may give more ideas of what to do sounds confusing but yes it does increase the influence sadly on violence out there . there is much evidence of many incidents where violence has happened sadly , like the columbine school shooting on april 20 of 1999 r.i.p to the innocent lives lost may they rest in peace ❤️also violent video games you can choose your choices on who to shoot and what to do and what to do not to get caught like gta 5 no hate on it i'm personally a big fan but you can choose to do bad or good on the game just like real life. people might illusion it in real life n try it out because in the video game it seems so realistic.