The page, which showed a photo of a baby with Down's with the word imbecile written on its forehead, said an easy and amusing solution for ridding the world of these foul creatures was to use them as target practice.
Italy will not tolerate incidents of discrimination of any sort, let alone against the disabled, Equality Minister Mara Carfagna told Italian television. Those responsible for creating this madness will be prosecuted by the law.
Down's syndrome is the most common genetic cause of mental retardation, occurring in 1 out of 700 live births.
Police are trying to track down those who set up the page. If caught, they could face up to 4-1/2 years imprisonment for incitement to committing a crime, the minister said.
The page drew protest and condemnation from politicians and disability support groups. Manuela Colombo, the president of the Down's syndrome support group Capirsi Down, condemned the offending website, saying: People's ignorance has no limits.
Those responsible should be made an example of, said Luca Zaia, Italy's agricultural minister. The first punishment could be to put them at the service of families with children with Down's syndrome whose dignity has been affronted.
Outrage over the anti-Down's site comes as four executives of the Italian branch of Google are on trial in Milan charged with defamation and failure to protect the privacy of a teenager with Down's who appeared in a video on a Google site in 2006.
The short video filmed with a mobile phone showed four Turin teenagers taunting the boy in front of a dozen other youths.
There are an estimated 38,000 people with Down's in the country, according to the Italian Down's Syndrome Association.
(Writing by Ella Ide; editing by Stephen Brown and Matthew Jones)