ABSTRACT
It is likely that there are subtypes of ASDs. For example, regression is seen in a certain proportion of cases. One recent study reported that regression was seen in 41% of a sample of 333 subjects with autism; 26% lost either language or social skills, while 15% lost both (Hansen et al., 2008). Other domains in which subtypes are likely include the presence or absence of behavioral in exibility, macrocephaly, seizures, and syndromic appearance.
