Savant Syndrome was first described by Langdon Down. In 1887 he used the term “idiot savant” to describe individuals with significant impairments in their mental abilities but with exceptional memory. Due to its inappropriate connotations and negative emphasis, instead of this term people use “Savant Syndrome.” Although ‘Autistic Savant’ is another term that’s used, this one is also open to misinterpretation because of it’s connection to autism; not all savant individuals have autism. Approximately 50% of individuals with Savant syndrome come from the autism population. It is known that the other 50% come from a population of developmental disabilities or individuals with central nervous system disorders. Approximately 10% of the autism population have Savant syndrome and less than 1% of other developmental disability categories. In order to understand Savant syndrome, it is necessary to know autism well.
Autism is a neurodevelopmental disorder and manifests itself with inadequate social interaction, limited interest and repetitive behavior. Autism is not a mental illness or disorder. Although the causes of autism are not fully known, it is assumed to have a genetic basis. However, the mechanisms of genetics that are in play have not been fully understood yet. Autism’s prevalence in boys is four or five times more than girls. In the group so-called high functioning autism, mental skills are normal or supernormal, but in individuals with low functioning autism, mental skills are below normal. With regard to intellectual abilities, between 30-40% of individuals with autism score lower than their neurotypical peers.
Because the causes of autism are not fully understood, there isn’t an effective treatment method yet. For now, the most effective treatment known is special education. The aim of education is to remove/attenuate the symptoms of autism and acquire new and positive behaviors in the areas where they exhibit inadequacy. Early education is exceedingly important for individuals with autism. Competent early education practices are based on the principles of Applied Behavior Analysis. Studies show that individuals with autism who receive qualified early education are able to continue with their lives with minimal support.
On the other hand, the term savant is used for pupils who exhibit highly unusual skills that are not present in other individuals with autism. Savant skills come in many forms. The most common ones are mathematics and computing skills, superior memory skills, artistic skills, and musical skills. Language and statistics oriented skills or having expert knowledge in a subject like computers are rarely seen. Individuals with autism are often calendrical savants (e.g. knowing which day January 15 falls on any given year.) At the same time, they can also do multiplication, division and square root calculations in their heads and do so very quickly. Whichever skill is displayed, these distinguished abilities are generally found centered around one specific skill; it is rarely seen across a variety of skills. It is not yet possible to diagnose Savant syndrome before birth.
Savant syndrome can be hereditary or acquired. In other words, it may be present at the time of birth and manifest itself in early childhood or may occur as a result of  damage to the central nervous system or a disease. It is seen in boys four to six times more than girls. Savant skills occur in individuals at different levels and affect everyone differently. Not every individual with Savant syndrome has autism, and vice versa – not every individual with autism has savant syndrome.
References

• Down, J. L. (1987). On some of the mental affections of childhood and youth. London: Churchill.
• Kırcaali-İftar, G. (2014). Otizm spektrum bozukluğuna genel bakış. E. Tekin-İftar (Editor). Otizm spektrum bozukluğu olan çocuklar ve eğitimleri. Ankara: Vize Yayıncılık.
• Treffert, D. A. (1988). The idiot savant: A review of the syndrome. American Journal of Psychiatry, 145(5), 563-572.
• Treffert, D. A. (1989). Extraordinary people: Understanding Savant Syndrome. Lincoln, NE: iUniverse.com.