There are no objectively definitive statistics about how many people have<unk>  skills. The estimates range from "exceedingly rare" to one in ten people with autism having<unk>  skills in varying degrees. A 2009 British study of 137 parents of autistic children found that 28% believe their children met the criteria for a<unk>  skill, defined as a skill or power "at a level that would be unusual even for 'normal' people". As many as 50 cases of sudden or acquired<unk>  have been reported. Males with<unk>  outnumber females by roughly 6:1 (in Finland), slightly higher than the sex ratio disparity for autism spectrum disorders of 4.3:1.
Savant syndrome
McGillivray syndrome
Witteveen–Kolk syndrome
Antley–Bixler syndrome
Gourmand syndrome
Havana syndrome
Zechi-Ceide syndrome
Bruck syndrome