A boy has been told his “next seizure could be his last” - after being diagnosed with one of the world’s rarest deadly diseases.<br /><br />William Howard, nine, was told by doctors his initial symptom, a twitch in his right leg, could be down to stress from playing Minecraft. <br /><br />But after “endless” medical investigations, an MRI confirmed he has mitochondrial disease - which means his cells won’t work correctly. <br />
