Q:

What do we call a person who cannot read people?

A person who has a low emotional IQ and is bad at reading people and decoding their expressions and body language. I don't think I need to give any statement for it.
Edit: They do not have any physical or mental disorders but more like lacking empathy but are not psychopaths. Looking for synonyms of 'socially illiterate'.

A:

That kind of person is "socially inept."
http://www.urbandictionary.com/define.php?term=Socially+Inept

A:

socially clumsy where clumsy, in particular:

awkward in movement or in handling things.

