Table I. Multiple rare variants in autism spectrum disorders (ASDs). While epidemiologically rigorous studies have yet to be carried out, there are reasonable estimates for the prevalence of some of the genetic contributors to ASDs. Some of the more common ones are shown here, together with some of the rare variants identified in recent studies.

Genetic etiology	Estimated prevalence in ASD
Karyotype abnormalities	5-10%
Fragile X syndrome	2%
15q abnormalities	2%
Tuberous sclerosis	1%
16p11 deletions	1%
22q13 deletions/SHANK3 abnormalities	0,75%
22q11 abnormalities	0,50%
Rett syndrome	0,10%
c30rf58 deletions, homozygous	Rare
CNTN4 deletions	Rare
DPP10 deletions	Rare
DPP6 Deletions	Rare
NHE9 deletions, homozygous	Rare
NLGN deletions/mutations	Rare
NRXN1 deletions	Rare
PCDH10 deletions, homozygous	Rare
PCDH9 deletions	Rare
PTEN mutations	Rare